diff --git a/backend/services/blockchain-service/src/api/controllers/internal.controller.ts b/backend/services/blockchain-service/src/api/controllers/internal.controller.ts
index f22b4f5d..8d965dce 100644
--- a/backend/services/blockchain-service/src/api/controllers/internal.controller.ts
+++ b/backend/services/blockchain-service/src/api/controllers/internal.controller.ts
@@ -1,9 +1,9 @@
-import { Controller, Post, Body, Get, Param } from '@nestjs/common';
+import { Controller, Post, Body, Get, Param, Put } from '@nestjs/common';
 import { ApiTags, ApiOperation, ApiResponse } from '@nestjs/swagger';
 import { AddressDerivationService } from '@/application/services/address-derivation.service';
 import { MnemonicVerificationService } from '@/application/services/mnemonic-verification.service';
 import { MnemonicDerivationAdapter } from '@/infrastructure/blockchain';
-import { DeriveAddressDto, VerifyMnemonicDto, VerifyMnemonicHashDto } from '../dto/request';
+import { DeriveAddressDto, VerifyMnemonicDto, VerifyMnemonicHashDto, MarkMnemonicBackupDto } from '../dto/request';
 import { DeriveAddressResponseDto } from '../dto/response';
 
 /**
@@ -23,10 +23,11 @@ export class InternalController {
   @ApiOperation({ summary: '从公钥派生地址' })
   @ApiResponse({ status: 201, description: '派生成功', type: DeriveAddressResponseDto })
   async deriveAddress(@Body() dto: DeriveAddressDto): Promise<DeriveAddressResponseDto> {
-    const result = await this.addressDerivationService.deriveAndRegister(
-      BigInt(dto.userId),
-      dto.publicKey,
-    );
+    const result = await this.addressDerivationService.deriveAndRegister({
+      userId: BigInt(dto.userId),
+      accountSequence: dto.accountSequence,
+      publicKey: dto.publicKey,
+    });
 
     return {
       userId: result.userId.toString(),
@@ -90,4 +91,15 @@ export class InternalController {
       message: result.message,
     };
   }
+
+  @Put('mnemonic/backup')
+  @ApiOperation({ summary: '标记助记词已备份' })
+  @ApiResponse({ status: 200, description: '标记成功' })
+  async markMnemonicBackedUp(@Body() dto: MarkMnemonicBackupDto) {
+    await this.mnemonicVerification.markAsBackedUp(dto.accountSequence);
+    return {
+      success: true,
+      message: 'Mnemonic marked as backed up',
+    };
+  }
 }
diff --git a/backend/services/blockchain-service/src/api/dto/request/derive-address.dto.ts b/backend/services/blockchain-service/src/api/dto/request/derive-address.dto.ts
index c38946c8..31d27e3e 100644
--- a/backend/services/blockchain-service/src/api/dto/request/derive-address.dto.ts
+++ b/backend/services/blockchain-service/src/api/dto/request/derive-address.dto.ts
@@ -1,4 +1,4 @@
-import { IsString, IsNumberString } from 'class-validator';
+import { IsString, IsNumberString, IsInt } from 'class-validator';
 import { ApiProperty } from '@nestjs/swagger';
 
 export class DeriveAddressDto {
@@ -6,6 +6,10 @@ export class DeriveAddressDto {
   @IsNumberString()
   userId: string;
 
+  @ApiProperty({ description: '账户序列号 (8位数字)', example: 10000001 })
+  @IsInt()
+  accountSequence: number;
+
   @ApiProperty({
     description: '压缩公钥 (33 bytes, 0x02/0x03 开头)',
     example: '0x02abc123...',
diff --git a/backend/services/blockchain-service/src/api/dto/request/index.ts b/backend/services/blockchain-service/src/api/dto/request/index.ts
index 5296a133..b65ae789 100644
--- a/backend/services/blockchain-service/src/api/dto/request/index.ts
+++ b/backend/services/blockchain-service/src/api/dto/request/index.ts
@@ -2,3 +2,4 @@ export * from './query-balance.dto';
 export * from './derive-address.dto';
 export * from './verify-mnemonic.dto';
 export * from './verify-mnemonic-hash.dto';
+export * from './mark-mnemonic-backup.dto';
diff --git a/backend/services/blockchain-service/src/api/dto/request/mark-mnemonic-backup.dto.ts b/backend/services/blockchain-service/src/api/dto/request/mark-mnemonic-backup.dto.ts
new file mode 100644
index 00000000..f078d8a8
--- /dev/null
+++ b/backend/services/blockchain-service/src/api/dto/request/mark-mnemonic-backup.dto.ts
@@ -0,0 +1,8 @@
+import { IsInt } from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
+
+export class MarkMnemonicBackupDto {
+  @ApiProperty({ description: '账户序列号 (8位数字)', example: 10000001 })
+  @IsInt()
+  accountSequence: number;
+}
diff --git a/backend/services/blockchain-service/src/application/event-handlers/mpc-keygen-completed.handler.ts b/backend/services/blockchain-service/src/application/event-handlers/mpc-keygen-completed.handler.ts
index 7eb20ac4..b8eb486f 100644
--- a/backend/services/blockchain-service/src/application/event-handlers/mpc-keygen-completed.handler.ts
+++ b/backend/services/blockchain-service/src/application/event-handlers/mpc-keygen-completed.handler.ts
@@ -25,7 +25,7 @@ export class MpcKeygenCompletedHandler implements OnModuleInit {
 
   /**
    * 处理 MPC 密钥生成完成事件
-   * 从 mpc-service 的 KeygenCompleted 事件中提取 publicKey 和 userId
+   * 从 mpc-service 的 KeygenCompleted 事件中提取 publicKey、userId 和 accountSequence
    */
   private async handleKeygenCompleted(payload: KeygenCompletedPayload): Promise<void> {
     this.logger.log(`[HANDLE] Received KeygenCompleted event`);
@@ -33,13 +33,20 @@ export class MpcKeygenCompletedHandler implements OnModuleInit {
     this.logger.log(`[HANDLE] publicKey: ${payload.publicKey?.substring(0, 30)}...`);
     this.logger.log(`[HANDLE] extraPayload: ${JSON.stringify(payload.extraPayload)}`);
 
-    // Extract userId from extraPayload
+    // Extract userId and accountSequence from extraPayload
     const userId = payload.extraPayload?.userId;
+    const accountSequence = payload.extraPayload?.accountSequence;
+
     if (!userId) {
       this.logger.error(`[ERROR] Missing userId in extraPayload, cannot derive addresses`);
       return;
     }
 
+    if (!accountSequence) {
+      this.logger.error(`[ERROR] Missing accountSequence in extraPayload, cannot derive addresses`);
+      return;
+    }
+
     const publicKey = payload.publicKey;
     if (!publicKey) {
       this.logger.error(`[ERROR] Missing publicKey in payload, cannot derive addresses`);
@@ -47,19 +54,20 @@ export class MpcKeygenCompletedHandler implements OnModuleInit {
     }
 
     try {
-      this.logger.log(`[DERIVE] Starting address derivation for user: ${userId}`);
+      this.logger.log(`[DERIVE] Starting address derivation for user: ${userId}, account: ${accountSequence}`);
 
-      const result = await this.addressDerivationService.deriveAndRegister(
-        BigInt(userId),
+      const result = await this.addressDerivationService.deriveAndRegister({
+        userId: BigInt(userId),
+        accountSequence: Number(accountSequence),
         publicKey,
-      );
+      });
 
-      this.logger.log(`[DERIVE] Successfully derived ${result.addresses.length} addresses for user ${userId}`);
+      this.logger.log(`[DERIVE] Successfully derived ${result.addresses.length} addresses for account ${accountSequence}`);
       result.addresses.forEach((addr) => {
         this.logger.log(`[DERIVE] - ${addr.chainType}: ${addr.address}`);
       });
     } catch (error) {
-      this.logger.error(`[ERROR] Failed to derive addresses for user ${userId}:`, error);
+      this.logger.error(`[ERROR] Failed to derive addresses for account ${accountSequence}:`, error);
       throw error;
     }
   }
diff --git a/backend/services/blockchain-service/src/application/services/address-derivation.service.ts b/backend/services/blockchain-service/src/application/services/address-derivation.service.ts
index 2543b5e1..3a318742 100644
--- a/backend/services/blockchain-service/src/application/services/address-derivation.service.ts
+++ b/backend/services/blockchain-service/src/application/services/address-derivation.service.ts
@@ -6,6 +6,7 @@ import {
 import { RecoveryMnemonicAdapter } from '@/infrastructure/blockchain/recovery-mnemonic.adapter';
 import { AddressCacheService } from '@/infrastructure/redis/address-cache.service';
 import { EventPublisherService } from '@/infrastructure/kafka/event-publisher.service';
+import { PrismaService } from '@/infrastructure/persistence/prisma/prisma.service';
 import {
   MONITORED_ADDRESS_REPOSITORY,
   IMonitoredAddressRepository,
@@ -15,8 +16,15 @@ import { WalletAddressCreatedEvent } from '@/domain/events';
 import { ChainType, EvmAddress } from '@/domain/value-objects';
 import { ChainTypeEnum } from '@/domain/enums';
 
+export interface DeriveAddressParams {
+  userId: bigint;
+  accountSequence: number;
+  publicKey: string;
+}
+
 export interface DeriveAddressResult {
   userId: bigint;
+  accountSequence: number;
   publicKey: string;
   addresses: DerivedAddress[];
 }
@@ -46,6 +54,7 @@ export class AddressDerivationService {
     private readonly recoveryMnemonic: RecoveryMnemonicAdapter,
     private readonly addressCache: AddressCacheService,
     private readonly eventPublisher: EventPublisherService,
+    private readonly prisma: PrismaService,
     @Inject(MONITORED_ADDRESS_REPOSITORY)
     private readonly monitoredAddressRepo: IMonitoredAddressRepository,
   ) {}
@@ -53,8 +62,9 @@ export class AddressDerivationService {
   /**
    * 从公钥派生地址并注册监控
    */
-  async deriveAndRegister(userId: bigint, publicKey: string): Promise<DeriveAddressResult> {
-    this.logger.log(`[DERIVE] Starting address derivation for user ${userId}`);
+  async deriveAndRegister(params: DeriveAddressParams): Promise<DeriveAddressResult> {
+    const { userId, accountSequence, publicKey } = params;
+    this.logger.log(`[DERIVE] Starting address derivation for user ${userId}, account ${accountSequence}`);
     this.logger.log(`[DERIVE] Public key: ${publicKey.substring(0, 30)}...`);
 
     // 1. 派生所有链的地址 (包括 Cosmos 和 EVM)
@@ -70,35 +80,50 @@ export class AddressDerivationService {
       }
     }
 
-    // 3. 生成恢复助记词 (与钱包公钥关联)
-    this.logger.log(`[MNEMONIC] Generating recovery mnemonic for user ${userId}`);
+    // 3. 生成恢复助记词 (与账户序列号关联)
+    this.logger.log(`[MNEMONIC] Generating recovery mnemonic for account ${accountSequence}`);
     const mnemonicResult = this.recoveryMnemonic.generateMnemonic({
       userId: userId.toString(),
       publicKey,
     });
     this.logger.log(`[MNEMONIC] Recovery mnemonic generated, hash: ${mnemonicResult.mnemonicHash.slice(0, 16)}...`);
 
-    // 4. 发布钱包地址创建事件 (包含所有链的地址和助记词)
+    // 4. 存储恢复助记词到 blockchain-service 数据库 (使用 accountSequence 关联)
+    await this.prisma.recoveryMnemonic.create({
+      data: {
+        accountSequence,
+        publicKey,
+        encryptedMnemonic: mnemonicResult.encryptedMnemonic,
+        mnemonicHash: mnemonicResult.mnemonicHash,
+        status: 'ACTIVE',
+        isBackedUp: false,
+      },
+    });
+    this.logger.log(`[MNEMONIC] Recovery mnemonic saved for account ${accountSequence}`);
+
+    // 5. 发布钱包地址创建事件 (包含所有链的地址和助记词)
     const event = new WalletAddressCreatedEvent({
       userId: userId.toString(),
+      accountSequence,
       publicKey,
       addresses: derivedAddresses.map((a) => ({
         chainType: a.chainType,
         address: a.address,
       })),
-      // 恢复助记词
+      // 恢复助记词 (明文仅在事件中传递给客户端首次显示)
       mnemonic: mnemonicResult.mnemonic,
       encryptedMnemonic: mnemonicResult.encryptedMnemonic,
       mnemonicHash: mnemonicResult.mnemonicHash,
     });
 
-    this.logger.log(`[PUBLISH] Publishing WalletAddressCreated event for user ${userId}`);
+    this.logger.log(`[PUBLISH] Publishing WalletAddressCreated event for account ${accountSequence}`);
     this.logger.log(`[PUBLISH] Addresses: ${JSON.stringify(derivedAddresses)}`);
     await this.eventPublisher.publish(event);
     this.logger.log(`[PUBLISH] WalletAddressCreated event published successfully`);
 
     return {
       userId,
+      accountSequence,
       publicKey,
       addresses: derivedAddresses,
     };
diff --git a/backend/services/blockchain-service/src/domain/events/wallet-address-created.event.ts b/backend/services/blockchain-service/src/domain/events/wallet-address-created.event.ts
index b67be787..4aefac7e 100644
--- a/backend/services/blockchain-service/src/domain/events/wallet-address-created.event.ts
+++ b/backend/services/blockchain-service/src/domain/events/wallet-address-created.event.ts
@@ -2,6 +2,7 @@ import { DomainEvent } from './domain-event.base';
 
 export interface WalletAddressCreatedPayload {
   userId: string;
+  accountSequence: number;        // 8位账户序列号
   publicKey: string;
   addresses: {
     chainType: string;
diff --git a/backend/services/blockchain-service/src/infrastructure/kafka/mpc-event-consumer.service.ts b/backend/services/blockchain-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
index 1d0ec019..92f37097 100644
--- a/backend/services/blockchain-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
+++ b/backend/services/blockchain-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
@@ -23,6 +23,7 @@ export interface KeygenCompletedPayload {
   threshold: string;
   extraPayload?: {
     userId: string;
+    accountSequence: number;  // 8位账户序列号，用于关联恢复助记词
     username: string;
     delegateShare?: {
       partyId: string;
diff --git a/backend/services/identity-service/src/application/event-handlers/blockchain-wallet.handler.ts b/backend/services/identity-service/src/application/event-handlers/blockchain-wallet.handler.ts
index 51019c3e..82b62906 100644
--- a/backend/services/identity-service/src/application/event-handlers/blockchain-wallet.handler.ts
+++ b/backend/services/identity-service/src/application/event-handlers/blockchain-wallet.handler.ts
@@ -103,10 +103,10 @@ export class BlockchainWalletHandler implements OnModuleInit {
       await this.userRepository.saveWallets(account.userId, wallets);
       this.logger.log(`[WALLET] Saved ${wallets.length} wallet addresses for user: ${userId}`);
 
-      // 4. Save recovery mnemonic if provided
-      if (mnemonic && encryptedMnemonic && mnemonicHash && publicKey) {
-        await this.saveRecoveryMnemonic(BigInt(userId), publicKey, encryptedMnemonic, mnemonicHash);
-        this.logger.log(`[MNEMONIC] Saved recovery mnemonic for user: ${userId}`);
+      // 4. Recovery mnemonic is now stored in blockchain-service (DDD: domain separation)
+      // Note: blockchain-service stores mnemonic with accountSequence association
+      if (mnemonic) {
+        this.logger.log(`[MNEMONIC] Recovery mnemonic received for user: ${userId} (stored in blockchain-service)`);
       }
 
       // 5. Update Redis status to completed (include mnemonic for first-time retrieval)
@@ -154,38 +154,4 @@ export class BlockchainWalletHandler implements OnModuleInit {
     }
   }
 
-  /**
-   * Save recovery mnemonic to database
-   */
-  private async saveRecoveryMnemonic(
-    userId: bigint,
-    publicKey: string,
-    encryptedMnemonic: string,
-    mnemonicHash: string,
-  ): Promise<void> {
-    // Check if mnemonic already exists for this user
-    const existing = await this.prisma.recoveryMnemonic.findFirst({
-      where: {
-        userId,
-        status: 'ACTIVE',
-      },
-    });
-
-    if (existing) {
-      this.logger.log(`[MNEMONIC] Active mnemonic already exists for user: ${userId}, skipping`);
-      return;
-    }
-
-    // Create new recovery mnemonic record
-    await this.prisma.recoveryMnemonic.create({
-      data: {
-        userId,
-        publicKey,
-        encryptedMnemonic,
-        mnemonicHash,
-        status: 'ACTIVE',
-        isBackedUp: false,
-      },
-    });
-  }
 }
diff --git a/backend/services/identity-service/src/application/services/user-application.service.ts b/backend/services/identity-service/src/application/services/user-application.service.ts
index c956fb55..f6333fdb 100644
--- a/backend/services/identity-service/src/application/services/user-application.service.ts
+++ b/backend/services/identity-service/src/application/services/user-application.service.ts
@@ -131,6 +131,7 @@ export class UserApplicationService {
     await this.eventPublisher.publish(new MpcKeygenRequestedEvent({
       sessionId,
       userId: account.userId.toString(),
+      accountSequence: account.accountSequence.value,  // 8位账户序列号，用于关联恢复助记词
       username: `user_${account.accountSequence.value}`, // 用于 mpc-system 标识
       threshold: 2,
       totalParties: 3,
@@ -688,11 +689,11 @@ export class UserApplicationService {
   /**
    * 获取用户的恢复助记词
    *
-   * 优先从 Redis 获取（首次生成时临时存储的明文）
-   * 如果 Redis 没有，从数据库获取（仅当用户未备份时返回）
+   * 只从 Redis 获取（首次生成时临时存储的明文）
+   * DDD: 助记词数据存储在 blockchain-service，identity-service 不直接访问
    */
   private async getRecoveryMnemonic(userId: bigint): Promise<string | null> {
-    // 1. 先从 Redis 获取首次生成的助记词
+    // 从 Redis 获取首次生成的助记词
     const redisKey = `keygen:status:${userId}`;
     const statusData = await this.redisService.get(redisKey);
 
@@ -704,27 +705,13 @@ export class UserApplicationService {
           return parsed.mnemonic;
         }
       } catch {
-        // 解析失败，继续从数据库获取
+        // 解析失败
       }
     }
 
-    // 2. 从数据库获取（仅当用户未备份时返回）
-    const recoveryMnemonic = await this.prisma.recoveryMnemonic.findFirst({
-      where: {
-        userId,
-        status: 'ACTIVE',
-        isBackedUp: false,  // 只有未备份时才返回
-      },
-    });
-
-    if (!recoveryMnemonic) {
-      this.logger.log(`[MNEMONIC] No active unbackuped mnemonic for user: ${userId}`);
-      return null;
-    }
-
-    // 返回空字符串，因为加密的助记词需要解密才能返回
-    // 实际应用中应该解密后返回，但这里为了安全，只在首次（Redis 中有时）返回
-    this.logger.log(`[MNEMONIC] Found encrypted mnemonic in DB for user: ${userId}, but not returning decrypted value`);
+    // Redis 中没有助记词，可能已经备份或过期
+    // DDD: 不再直接从 identity-service 数据库获取，助记词数据在 blockchain-service
+    this.logger.log(`[MNEMONIC] No mnemonic in Redis for user: ${userId} (may be backed up or expired)`);
     return null;
   }
 
@@ -734,33 +721,30 @@ export class UserApplicationService {
    * 标记助记词已备份 (PUT /user/mnemonic/backup)
    *
    * 用户确认已备份助记词后调用此接口：
-   * 1. 更新数据库 isBackedUp = true
+   * 1. 调用 blockchain-service 更新 isBackedUp = true (DDD: domain separation)
    * 2. 清除 Redis 中的明文助记词
    */
   async markMnemonicBackedUp(command: MarkMnemonicBackedUpCommand): Promise<void> {
     const userId = BigInt(command.userId);
     this.logger.log(`[BACKUP] Marking mnemonic as backed up for user: ${userId}`);
 
-    // 1. 更新数据库
-    const result = await this.prisma.recoveryMnemonic.updateMany({
-      where: {
-        userId,
-        status: 'ACTIVE',
-        isBackedUp: false,
-      },
-      data: {
-        isBackedUp: true,
-      },
-    });
-
-    if (result.count === 0) {
-      this.logger.warn(`[BACKUP] No active unbackuped mnemonic found for user: ${userId}`);
-      // 不抛出错误，可能已经备份过了
-    } else {
-      this.logger.log(`[BACKUP] Mnemonic marked as backed up for user: ${userId}`);
+    // 1. 获取用户的 accountSequence
+    const account = await this.userRepository.findById(UserId.create(command.userId));
+    if (!account) {
+      this.logger.warn(`[BACKUP] User not found: ${userId}`);
+      return;
     }
 
-    // 2. 清除 Redis 中的明文助记词（更新状态，移除 mnemonic 字段）
+    // 2. 调用 blockchain-service 标记助记词已备份 (DDD: domain separation)
+    try {
+      await this.blockchainClient.markMnemonicBackedUp(account.accountSequence.value);
+      this.logger.log(`[BACKUP] Mnemonic marked as backed up in blockchain-service for account: ${account.accountSequence.value}`);
+    } catch (error) {
+      this.logger.error(`[BACKUP] Failed to mark mnemonic as backed up in blockchain-service`, error);
+      // 不阻塞，继续清除 Redis
+    }
+
+    // 3. 清除 Redis 中的明文助记词（更新状态，移除 mnemonic 字段）
     const redisKey = `keygen:status:${userId}`;
     const statusData = await this.redisService.get(redisKey);
 
diff --git a/backend/services/identity-service/src/domain/events/index.ts b/backend/services/identity-service/src/domain/events/index.ts
index 96aab63d..066b86d3 100644
--- a/backend/services/identity-service/src/domain/events/index.ts
+++ b/backend/services/identity-service/src/domain/events/index.ts
@@ -166,6 +166,7 @@ export class UserAccountDeactivatedEvent extends DomainEvent {
  * payload 格式需要与 mpc-service 的 KeygenRequestedPayload 匹配:
  * - sessionId: 唯一会话ID
  * - userId: 用户ID
+ * - accountSequence: 8位账户序列号 (用于关联恢复助记词)
  * - username: 用户名 (用于 mpc-system 标识)
  * - threshold: 签名阈值 (默认 2)
  * - totalParties: 总参与方数 (默认 3)
@@ -176,6 +177,7 @@ export class MpcKeygenRequestedEvent extends DomainEvent {
     public readonly payload: {
       sessionId: string;
       userId: string;
+      accountSequence: number;
       username: string;
       threshold: number;
       totalParties: number;
diff --git a/backend/services/identity-service/src/infrastructure/external/blockchain/blockchain-client.service.ts b/backend/services/identity-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
index 78118ebf..26eb7a54 100644
--- a/backend/services/identity-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
+++ b/backend/services/identity-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
@@ -140,4 +140,29 @@ export class BlockchainClientService {
       throw error;
     }
   }
+
+  /**
+   * 标记助记词已备份
+   */
+  async markMnemonicBackedUp(accountSequence: number): Promise<void> {
+    this.logger.log(`Marking mnemonic as backed up for account ${accountSequence}`);
+
+    try {
+      await firstValueFrom(
+        this.httpService.put(
+          `${this.blockchainServiceUrl}/internal/mnemonic/backup`,
+          { accountSequence },
+          {
+            headers: { 'Content-Type': 'application/json' },
+            timeout: 30000,
+          },
+        ),
+      );
+
+      this.logger.log(`Mnemonic marked as backed up for account ${accountSequence}`);
+    } catch (error) {
+      this.logger.error('Failed to mark mnemonic as backed up', error);
+      throw error;
+    }
+  }
 }
diff --git a/backend/services/identity-service/src/infrastructure/kafka/mpc-event-consumer.service.ts b/backend/services/identity-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
index 9e5f4df6..39cabc97 100644
--- a/backend/services/identity-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
+++ b/backend/services/identity-service/src/infrastructure/kafka/mpc-event-consumer.service.ts
@@ -32,6 +32,7 @@ export interface KeygenCompletedPayload {
   threshold: string;
   extraPayload?: {
     userId: string;
+    accountSequence: number;  // 8位账户序列号
     username: string;
     delegateShare?: {
       partyId: string;
diff --git a/backend/services/mpc-service/src/application/event-handlers/keygen-requested.handler.ts b/backend/services/mpc-service/src/application/event-handlers/keygen-requested.handler.ts
index ee1a6b37..20dfaf0a 100644
--- a/backend/services/mpc-service/src/application/event-handlers/keygen-requested.handler.ts
+++ b/backend/services/mpc-service/src/application/event-handlers/keygen-requested.handler.ts
@@ -46,7 +46,7 @@ export class KeygenRequestedHandler implements OnModuleInit {
     this.logger.log(`[HANDLE] Payload: ${JSON.stringify(payload)}`);
 
     const data = payload as unknown as KeygenRequestedPayload;
-    const { sessionId, userId, username, threshold, totalParties, requireDelegate } = data;
+    const { sessionId, userId, accountSequence, username, threshold, totalParties, requireDelegate } = data;
 
     this.logger.log(`[HANDLE] Parsed request: sessionId=${sessionId}`);
     this.logger.log(`[HANDLE] userId=${userId}, username=${username}`);
@@ -81,6 +81,7 @@ export class KeygenRequestedHandler implements OnModuleInit {
         try {
           const deriveResult = await this.blockchainClient.deriveAddresses({
             userId,
+            accountSequence,  // 8位账户序列号，用于关联恢复助记词
             publicKey: result.publicKey,
           });
           derivedAddresses = deriveResult.addresses;
@@ -129,6 +130,7 @@ export class KeygenRequestedHandler implements OnModuleInit {
         // Add extra payload for identity-service
         (completedEvent as any).extraPayload = {
           userId,
+          accountSequence,  // 8位账户序列号，用于关联恢复助记词
           username,
           delegateShare: result.delegateShare,
           derivedAddresses, // BSC, KAVA, DST addresses
diff --git a/backend/services/mpc-service/src/infrastructure/external/blockchain/blockchain-client.service.ts b/backend/services/mpc-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
index 6e3ba935..8ab49270 100644
--- a/backend/services/mpc-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
+++ b/backend/services/mpc-service/src/infrastructure/external/blockchain/blockchain-client.service.ts
@@ -11,6 +11,7 @@ import { firstValueFrom } from 'rxjs';
 
 export interface DeriveAddressParams {
   userId: string;
+  accountSequence: number;  // 8位账户序列号，用于关联恢复助记词
   publicKey: string;
 }
 
@@ -54,6 +55,7 @@ export class BlockchainClientService {
           `${this.blockchainServiceUrl}/api/v1/internal/derive-address`,
           {
             userId: params.userId,
+            accountSequence: params.accountSequence,
             publicKey: params.publicKey,
           },
           {
diff --git a/backend/services/mpc-service/src/infrastructure/messaging/kafka/event-consumer.service.ts b/backend/services/mpc-service/src/infrastructure/messaging/kafka/event-consumer.service.ts
index e2208e01..6cb66004 100644
--- a/backend/services/mpc-service/src/infrastructure/messaging/kafka/event-consumer.service.ts
+++ b/backend/services/mpc-service/src/infrastructure/messaging/kafka/event-consumer.service.ts
@@ -18,6 +18,7 @@ export const MPC_CONSUME_TOPICS = {
 export interface KeygenRequestedPayload {
   sessionId: string;
   userId: string;
+  accountSequence: number;  // 8位账户序列号，用于关联恢复助记词
   username: string;
   threshold: number;
   totalParties: number;