diff --git a/backend/services/identity-service/src/application/commands/auto-create-account/auto-create-account.handler.ts b/backend/services/identity-service/src/application/commands/auto-create-account/auto-create-account.handler.ts
index 54a2ebc6..38588a1e 100644
--- a/backend/services/identity-service/src/application/commands/auto-create-account/auto-create-account.handler.ts
+++ b/backend/services/identity-service/src/application/commands/auto-create-account/auto-create-account.handler.ts
@@ -55,7 +55,7 @@ export class AutoCreateAccountHandler {
     await this.userRepository.saveWallets(account.userId, Array.from(wallets.values()));
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.deviceId,
     });
@@ -64,7 +64,7 @@ export class AutoCreateAccountHandler {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       referralCode: account.referralCode.value,
       mnemonic: mnemonic.value,
diff --git a/backend/services/identity-service/src/application/commands/recover-by-mnemonic/recover-by-mnemonic.handler.ts b/backend/services/identity-service/src/application/commands/recover-by-mnemonic/recover-by-mnemonic.handler.ts
index 5246391d..b9ffa954 100644
--- a/backend/services/identity-service/src/application/commands/recover-by-mnemonic/recover-by-mnemonic.handler.ts
+++ b/backend/services/identity-service/src/application/commands/recover-by-mnemonic/recover-by-mnemonic.handler.ts
@@ -41,7 +41,7 @@ export class RecoverByMnemonicHandler {
     await this.userRepository.save(account);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.newDeviceId,
     });
@@ -50,7 +50,7 @@ export class RecoverByMnemonicHandler {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
       avatarUrl: account.avatarUrl,
diff --git a/backend/services/identity-service/src/application/commands/recover-by-phone/recover-by-phone.handler.ts b/backend/services/identity-service/src/application/commands/recover-by-phone/recover-by-phone.handler.ts
index cebd6d23..639bda58 100644
--- a/backend/services/identity-service/src/application/commands/recover-by-phone/recover-by-phone.handler.ts
+++ b/backend/services/identity-service/src/application/commands/recover-by-phone/recover-by-phone.handler.ts
@@ -37,7 +37,7 @@ export class RecoverByPhoneHandler {
     await this.redisService.delete(`sms:recover:${phoneNumber.value}`);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.newDeviceId,
     });
@@ -46,7 +46,7 @@ export class RecoverByPhoneHandler {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
       avatarUrl: account.avatarUrl,
diff --git a/backend/services/identity-service/src/application/queries/get-my-profile/get-my-profile.handler.ts b/backend/services/identity-service/src/application/queries/get-my-profile/get-my-profile.handler.ts
index 8d5d67c1..40e3d189 100644
--- a/backend/services/identity-service/src/application/queries/get-my-profile/get-my-profile.handler.ts
+++ b/backend/services/identity-service/src/application/queries/get-my-profile/get-my-profile.handler.ts
@@ -21,7 +21,7 @@ export class GetMyProfileHandler {
 
   private toDTO(account: UserAccount): UserProfileDTO {
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       phoneNumber: account.phoneNumber?.masked() || null,
       nickname: account.nickname,
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 d38bbba7..a6506bcf 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
@@ -70,7 +70,7 @@ export class UserApplicationService {
     await this.userRepository.saveWallets(account.userId, Array.from(wallets.values()));
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.deviceId,
     });
@@ -79,7 +79,7 @@ export class UserApplicationService {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       referralCode: account.referralCode.value,
       mnemonic: mnemonic.value,
@@ -116,7 +116,7 @@ export class UserApplicationService {
     await this.userRepository.save(account);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.newDeviceId,
     });
@@ -125,7 +125,7 @@ export class UserApplicationService {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
       avatarUrl: account.avatarUrl,
@@ -154,7 +154,7 @@ export class UserApplicationService {
     await this.redisService.delete(`sms:recover:${phoneNumber.value}`);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.newDeviceId,
     });
@@ -163,7 +163,7 @@ export class UserApplicationService {
     account.clearDomainEvents();
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
       avatarUrl: account.avatarUrl,
@@ -186,13 +186,13 @@ export class UserApplicationService {
     await this.userRepository.save(account);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.deviceId,
     });
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       accessToken: tokens.accessToken,
       refreshToken: tokens.refreshToken,
@@ -243,13 +243,13 @@ export class UserApplicationService {
     account.clearDomainEvents();
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.deviceId,
     });
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       referralCode: account.referralCode.value,
       accessToken: tokens.accessToken,
@@ -272,13 +272,13 @@ export class UserApplicationService {
     await this.redisService.delete(`sms:login:${phoneNumber.value}`);
 
     const tokens = await this.tokenService.generateTokenPair({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       deviceId: command.deviceId,
     });
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       accessToken: tokens.accessToken,
       refreshToken: tokens.refreshToken,
@@ -370,7 +370,7 @@ export class UserApplicationService {
 
     account.removeDevice(command.deviceIdToRemove);
     await this.userRepository.save(account);
-    await this.tokenService.revokeDeviceTokens(account.userId.value, command.deviceIdToRemove);
+    await this.tokenService.revokeDeviceTokens(account.userId.toString(), command.deviceIdToRemove);
     await this.eventPublisher.publishAll(account.domainEvents);
     account.clearDomainEvents();
   }
@@ -386,7 +386,7 @@ export class UserApplicationService {
     if (!account) return null;
 
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
       avatarUrl: account.avatarUrl,
@@ -395,7 +395,7 @@ export class UserApplicationService {
 
   private toUserProfileDTO(account: UserAccount): UserProfileDTO {
     return {
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       phoneNumber: account.phoneNumber?.masked() || null,
       nickname: account.nickname,
diff --git a/backend/services/identity-service/src/domain/aggregates/user-account/user-account.aggregate.ts b/backend/services/identity-service/src/domain/aggregates/user-account/user-account.aggregate.ts
index dd379b0a..f5743f50 100644
--- a/backend/services/identity-service/src/domain/aggregates/user-account/user-account.aggregate.ts
+++ b/backend/services/identity-service/src/domain/aggregates/user-account/user-account.aggregate.ts
@@ -106,7 +106,7 @@ export class UserAccount {
     );
 
     account.addDomainEvent(new UserAccountAutoCreatedEvent({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: params.accountSequence.value,
       initialDeviceId: params.initialDeviceId,
       inviterSequence: params.inviterSequence?.value || null,
@@ -132,8 +132,9 @@ export class UserAccount {
       params.initialDeviceId, params.deviceName || '未命名设备', new Date(), new Date(),
     ));
 
+    // UserID将由数据库自动生成(autoincrement)，这里使用临时值0
     const account = new UserAccount(
-      UserId.generate(), params.accountSequence, devices, params.phoneNumber,
+      UserId.create(0), params.accountSequence, devices, params.phoneNumber,
       `用户${params.accountSequence.value}`, null, params.inviterSequence,
       ReferralCode.generate(), params.province, params.city, null,
       new Map(), null, KYCStatus.NOT_VERIFIED, AccountStatus.ACTIVE,
@@ -141,7 +142,7 @@ export class UserAccount {
     );
 
     account.addDomainEvent(new UserAccountCreatedEvent({
-      userId: account.userId.value,
+      userId: account.userId.toString(),
       accountSequence: params.accountSequence.value,
       phoneNumber: params.phoneNumber.value,
       initialDeviceId: params.initialDeviceId,
@@ -201,7 +202,7 @@ export class UserAccount {
     } else {
       this._devices.set(deviceId, new DeviceInfo(deviceId, deviceName || '未命名设备', new Date(), new Date()));
       this.addDomainEvent(new DeviceAddedEvent({
-        userId: this.userId.value,
+        userId: this.userId.toString(),
         accountSequence: this.accountSequence.value,
         deviceId,
         deviceName: deviceName || '未命名设备',
@@ -216,7 +217,7 @@ export class UserAccount {
     if (this._devices.size <= 1) throw new DomainError('至少保留一个设备');
     this._devices.delete(deviceId);
     this._updatedAt = new Date();
-    this.addDomainEvent(new DeviceRemovedEvent({ userId: this.userId.value, deviceId }));
+    this.addDomainEvent(new DeviceRemovedEvent({ userId: this.userId.toString(), deviceId }));
   }
 
   isDeviceAuthorized(deviceId: string): boolean {
@@ -241,7 +242,7 @@ export class UserAccount {
     this._city = city;
     this._updatedAt = new Date();
     this.addDomainEvent(new UserLocationUpdatedEvent({
-      userId: this.userId.value, province: province.value, city: city.value,
+      userId: this.userId.toString(), province: province.value, city: city.value,
     }));
   }
 
@@ -250,7 +251,7 @@ export class UserAccount {
     if (this._phoneNumber) throw new DomainError('已绑定手机号,不可重复绑定');
     this._phoneNumber = phoneNumber;
     this._updatedAt = new Date();
-    this.addDomainEvent(new PhoneNumberBoundEvent({ userId: this.userId.value, phoneNumber: phoneNumber.value }));
+    this.addDomainEvent(new PhoneNumberBoundEvent({ userId: this.userId.toString(), phoneNumber: phoneNumber.value }));
   }
 
   bindWalletAddress(chainType: ChainType, address: string): void {
@@ -259,7 +260,7 @@ export class UserAccount {
     const walletAddress = WalletAddress.create({ userId: this.userId, chainType, address });
     this._walletAddresses.set(chainType, walletAddress);
     this._updatedAt = new Date();
-    this.addDomainEvent(new WalletAddressBoundEvent({ userId: this.userId.value, chainType, address }));
+    this.addDomainEvent(new WalletAddressBoundEvent({ userId: this.userId.toString(), chainType, address }));
   }
 
   bindMultipleWalletAddresses(wallets: Map<ChainType, WalletAddress>): void {
@@ -270,7 +271,7 @@ export class UserAccount {
     }
     this._updatedAt = new Date();
     this.addDomainEvent(new MultipleWalletAddressesBoundEvent({
-      userId: this.userId.value,
+      userId: this.userId.toString(),
       addresses: Array.from(wallets.entries()).map(([chainType, wallet]) => ({ chainType, address: wallet.address })),
     }));
   }
@@ -282,7 +283,7 @@ export class UserAccount {
     this._kycStatus = KYCStatus.PENDING;
     this._updatedAt = new Date();
     this.addDomainEvent(new KYCSubmittedEvent({
-      userId: this.userId.value, realName: kycInfo.realName, idCardNumber: kycInfo.idCardNumber,
+      userId: this.userId.toString(), realName: kycInfo.realName, idCardNumber: kycInfo.idCardNumber,
     }));
   }
 
@@ -290,14 +291,14 @@ export class UserAccount {
     if (this._kycStatus !== KYCStatus.PENDING) throw new DomainError('只有待审核状态才能通过KYC');
     this._kycStatus = KYCStatus.VERIFIED;
     this._updatedAt = new Date();
-    this.addDomainEvent(new KYCVerifiedEvent({ userId: this.userId.value, verifiedAt: new Date() }));
+    this.addDomainEvent(new KYCVerifiedEvent({ userId: this.userId.toString(), verifiedAt: new Date() }));
   }
 
   rejectKYC(reason: string): void {
     if (this._kycStatus !== KYCStatus.PENDING) throw new DomainError('只有待审核状态才能拒绝KYC');
     this._kycStatus = KYCStatus.REJECTED;
     this._updatedAt = new Date();
-    this.addDomainEvent(new KYCRejectedEvent({ userId: this.userId.value, reason }));
+    this.addDomainEvent(new KYCRejectedEvent({ userId: this.userId.toString(), reason }));
   }
 
   recordLogin(): void {
@@ -310,7 +311,7 @@ export class UserAccount {
     if (this._status === AccountStatus.FROZEN) throw new DomainError('账户已冻结');
     this._status = AccountStatus.FROZEN;
     this._updatedAt = new Date();
-    this.addDomainEvent(new UserAccountFrozenEvent({ userId: this.userId.value, reason }));
+    this.addDomainEvent(new UserAccountFrozenEvent({ userId: this.userId.toString(), reason }));
   }
 
   unfreeze(): void {
@@ -323,7 +324,7 @@ export class UserAccount {
     if (this._status === AccountStatus.DEACTIVATED) throw new DomainError('账户已注销');
     this._status = AccountStatus.DEACTIVATED;
     this._updatedAt = new Date();
-    this.addDomainEvent(new UserAccountDeactivatedEvent({ userId: this.userId.value, deactivatedAt: new Date() }));
+    this.addDomainEvent(new UserAccountDeactivatedEvent({ userId: this.userId.toString(), deactivatedAt: new Date() }));
   }
 
   getWalletAddress(chainType: ChainType): WalletAddress | null {
diff --git a/backend/services/identity-service/src/domain/services/index.ts b/backend/services/identity-service/src/domain/services/index.ts
index 52dc56e3..ba520cd1 100644
--- a/backend/services/identity-service/src/domain/services/index.ts
+++ b/backend/services/identity-service/src/domain/services/index.ts
@@ -78,7 +78,7 @@ export class WalletGeneratorService {
     wallets: Map<ChainType, WalletAddress>;
   } {
     const mnemonic = Mnemonic.generate();
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
 
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
@@ -97,7 +97,7 @@ export class WalletGeneratorService {
   }
 
   recoverWalletSystem(params: { userId: UserId; mnemonic: Mnemonic; deviceId: string }): Map<ChainType, WalletAddress> {
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
 
diff --git a/backend/services/identity-service/src/domain/services/wallet-generator.service.ts b/backend/services/identity-service/src/domain/services/wallet-generator.service.ts
index 5ee9af64..a9e1eaaa 100644
--- a/backend/services/identity-service/src/domain/services/wallet-generator.service.ts
+++ b/backend/services/identity-service/src/domain/services/wallet-generator.service.ts
@@ -10,7 +10,7 @@ export class WalletGeneratorService {
     wallets: Map<ChainType, WalletAddress>;
   } {
     const mnemonic = Mnemonic.generate();
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
 
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
@@ -29,7 +29,7 @@ export class WalletGeneratorService {
   }
 
   recoverWalletSystem(params: { userId: UserId; mnemonic: Mnemonic; deviceId: string }): Map<ChainType, WalletAddress> {
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
 
diff --git a/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.impl.ts b/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.impl.ts
index f1d3d40a..44262993 100644
--- a/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.impl.ts
+++ b/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.impl.ts
@@ -10,7 +10,7 @@ export class WalletGeneratorServiceImpl {
     wallets: Map<ChainType, WalletAddress>;
   } {
     const mnemonic = Mnemonic.generate();
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
 
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
@@ -29,7 +29,7 @@ export class WalletGeneratorServiceImpl {
   }
 
   recoverWalletSystem(params: { userId: UserId; mnemonic: Mnemonic; deviceId: string }): Map<ChainType, WalletAddress> {
-    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.value);
+    const encryptionKey = this.deriveEncryptionKey(params.deviceId, params.userId.toString());
     const wallets = new Map<ChainType, WalletAddress>();
     const chains = [ChainType.KAVA, ChainType.DST, ChainType.BSC];
 
diff --git a/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.ts b/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.ts
index bd78e02e..8a5cacb0 100644
--- a/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.ts
+++ b/backend/services/identity-service/src/infrastructure/external/blockchain/wallet-generator.service.ts
@@ -13,7 +13,6 @@ import { ConfigService } from '@nestjs/config';
 import { Mnemonic, UserId, ChainType, CHAIN_CONFIG } from '@/domain/value-objects';
 import { WalletAddress } from '@/domain/entities/wallet-address.entity';
 import { DomainError } from '@/shared/exceptions/domain.exception';
-import { v4 as uuidv4 } from 'uuid';
 
 export interface WalletSystemResult {
   mnemonic: Mnemonic;