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 8d965dce..770b0f0d 100644
--- a/backend/services/blockchain-service/src/api/controllers/internal.controller.ts
+++ b/backend/services/blockchain-service/src/api/controllers/internal.controller.ts
@@ -3,7 +3,7 @@ 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, MarkMnemonicBackupDto } from '../dto/request';
+import { DeriveAddressDto, VerifyMnemonicDto, VerifyMnemonicHashDto, MarkMnemonicBackupDto, RevokeMnemonicDto } from '../dto/request';
 import { DeriveAddressResponseDto } from '../dto/response';
 
 /**
@@ -102,4 +102,12 @@ export class InternalController {
       message: 'Mnemonic marked as backed up',
     };
   }
+
+  @Post('mnemonic/revoke')
+  @ApiOperation({ summary: '挂失助记词' })
+  @ApiResponse({ status: 200, description: '挂失结果' })
+  async revokeMnemonic(@Body() dto: RevokeMnemonicDto) {
+    const result = await this.mnemonicVerification.revokeMnemonic(dto.accountSequence, dto.reason);
+    return result;
+  }
 }
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 b65ae789..d0ec70ab 100644
--- a/backend/services/blockchain-service/src/api/dto/request/index.ts
+++ b/backend/services/blockchain-service/src/api/dto/request/index.ts
@@ -3,3 +3,4 @@ export * from './derive-address.dto';
 export * from './verify-mnemonic.dto';
 export * from './verify-mnemonic-hash.dto';
 export * from './mark-mnemonic-backup.dto';
+export * from './revoke-mnemonic.dto';
diff --git a/backend/services/blockchain-service/src/api/dto/request/revoke-mnemonic.dto.ts b/backend/services/blockchain-service/src/api/dto/request/revoke-mnemonic.dto.ts
new file mode 100644
index 00000000..ae2c1b78
--- /dev/null
+++ b/backend/services/blockchain-service/src/api/dto/request/revoke-mnemonic.dto.ts
@@ -0,0 +1,15 @@
+import { IsString, IsNotEmpty, MaxLength } from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
+
+export class RevokeMnemonicDto {
+  @ApiProperty({ example: 'D2512110001', description: '账户序列号' })
+  @IsString()
+  @IsNotEmpty()
+  accountSequence: string;
+
+  @ApiProperty({ example: '助记词泄露', description: '挂失原因' })
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(200)
+  reason: string;
+}
diff --git a/backend/services/blockchain-service/src/application/services/mnemonic-verification.service.ts b/backend/services/blockchain-service/src/application/services/mnemonic-verification.service.ts
index 163a8e56..d166fa17 100644
--- a/backend/services/blockchain-service/src/application/services/mnemonic-verification.service.ts
+++ b/backend/services/blockchain-service/src/application/services/mnemonic-verification.service.ts
@@ -100,4 +100,57 @@ export class MnemonicVerificationService {
     });
     this.logger.log(`Recovery mnemonic marked as backed up for account ${accountSequence}`);
   }
+
+  /**
+   * 挂失助记词
+   * 将 ACTIVE 状态的助记词标记为 REVOKED
+   */
+  async revokeMnemonic(accountSequence: string, reason: string): Promise<{ success: boolean; message: string }> {
+    this.logger.log(`Revoking mnemonic for account ${accountSequence}, reason: ${reason}`);
+
+    // 查找 ACTIVE 状态的助记词
+    const activeRecord = await this.prisma.recoveryMnemonic.findFirst({
+      where: {
+        accountSequence,
+        status: 'ACTIVE',
+      },
+    });
+
+    if (!activeRecord) {
+      this.logger.warn(`No active mnemonic found for account ${accountSequence}`);
+      return {
+        success: false,
+        message: '该账户没有可挂失的助记词',
+      };
+    }
+
+    // 更新状态为 REVOKED
+    await this.prisma.recoveryMnemonic.update({
+      where: { id: activeRecord.id },
+      data: {
+        status: 'REVOKED',
+        revokedAt: new Date(),
+        revokedReason: reason,
+      },
+    });
+
+    this.logger.log(`Mnemonic revoked successfully for account ${accountSequence}`);
+    return {
+      success: true,
+      message: '助记词已挂失',
+    };
+  }
+
+  /**
+   * 检查助记词是否已挂失
+   */
+  async isMnemonicRevoked(accountSequence: string): Promise<boolean> {
+    const revokedRecord = await this.prisma.recoveryMnemonic.findFirst({
+      where: {
+        accountSequence,
+        status: 'REVOKED',
+      },
+    });
+    return !!revokedRecord;
+  }
 }
diff --git a/backend/services/identity-service/src/api/controllers/user-account.controller.ts b/backend/services/identity-service/src/api/controllers/user-account.controller.ts
index 8e7748d3..becf3cc3 100644
--- a/backend/services/identity-service/src/api/controllers/user-account.controller.ts
+++ b/backend/services/identity-service/src/api/controllers/user-account.controller.ts
@@ -17,7 +17,7 @@ import {
 import {
   AutoCreateAccountDto, RecoverByMnemonicDto, RecoverByPhoneDto, AutoLoginDto,
   SendSmsCodeDto, RegisterDto, LoginDto, BindPhoneDto, UpdateProfileDto,
-  BindWalletDto, SubmitKYCDto, RemoveDeviceDto,
+  BindWalletDto, SubmitKYCDto, RemoveDeviceDto, RevokeMnemonicDto,
   AutoCreateAccountResponseDto, RecoverAccountResponseDto, LoginResponseDto,
   UserProfileResponseDto, DeviceResponseDto,
   WalletStatusReadyResponseDto, WalletStatusGeneratingResponseDto,
@@ -198,6 +198,14 @@ export class UserAccountController {
     return { message: '已标记为已备份' };
   }
 
+  @Post('mnemonic/revoke')
+  @ApiBearerAuth()
+  @ApiOperation({ summary: '挂失助记词', description: '用户主动挂失助记词，挂失后该助记词将无法用于账户恢复' })
+  @ApiResponse({ status: 200, description: '挂失结果' })
+  async revokeMnemonic(@CurrentUser() user: CurrentUserData, @Body() dto: RevokeMnemonicDto) {
+    return this.userService.revokeMnemonic(user.userId, dto.reason);
+  }
+
   @Post('upload-avatar')
   @ApiBearerAuth()
   @ApiOperation({ summary: '上传用户头像' })
diff --git a/backend/services/identity-service/src/api/dto/request/index.ts b/backend/services/identity-service/src/api/dto/request/index.ts
index 9dcbabe5..b524c6ef 100644
--- a/backend/services/identity-service/src/api/dto/request/index.ts
+++ b/backend/services/identity-service/src/api/dto/request/index.ts
@@ -3,3 +3,4 @@ export * from './recover-by-mnemonic.dto';
 export * from './recover-by-phone.dto';
 export * from './bind-phone.dto';
 export * from './submit-kyc.dto';
+export * from './revoke-mnemonic.dto';
diff --git a/backend/services/identity-service/src/api/dto/request/revoke-mnemonic.dto.ts b/backend/services/identity-service/src/api/dto/request/revoke-mnemonic.dto.ts
new file mode 100644
index 00000000..97d65a18
--- /dev/null
+++ b/backend/services/identity-service/src/api/dto/request/revoke-mnemonic.dto.ts
@@ -0,0 +1,10 @@
+import { IsString, IsNotEmpty, MaxLength } from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
+
+export class RevokeMnemonicDto {
+  @ApiProperty({ example: '助记词泄露', description: '挂失原因' })
+  @IsString()
+  @IsNotEmpty({ message: '请填写挂失原因' })
+  @MaxLength(200, { message: '挂失原因不能超过200字' })
+  reason: string;
+}
diff --git a/backend/services/identity-service/src/application/commands/revoke-mnemonic/revoke-mnemonic.command.ts b/backend/services/identity-service/src/application/commands/revoke-mnemonic/revoke-mnemonic.command.ts
new file mode 100644
index 00000000..287d8e54
--- /dev/null
+++ b/backend/services/identity-service/src/application/commands/revoke-mnemonic/revoke-mnemonic.command.ts
@@ -0,0 +1,7 @@
+export class RevokeMnemonicCommand {
+  constructor(
+    public readonly userId: string,
+    public readonly accountSequence: string,
+    public readonly reason: string,
+  ) {}
+}
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 ce3de2a3..9c7349f3 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
@@ -775,4 +775,33 @@ export class UserApplicationService {
       }
     }
   }
+
+  // ============ 助记词挂失相关 ============
+
+  /**
+   * 挂失助记词 (POST /user/mnemonic/revoke)
+   *
+   * 用户主动挂失助记词，防止泄露后被滥用
+   * 挂失后该助记词将无法用于账户恢复
+   */
+  async revokeMnemonic(userId: string, reason: string): Promise<{ success: boolean; message: string }> {
+    this.logger.log(`[REVOKE] Revoking mnemonic for user: ${userId}, reason: ${reason}`);
+
+    // 1. 获取用户的 accountSequence
+    const account = await this.userRepository.findById(UserId.create(userId));
+    if (!account) {
+      this.logger.warn(`[REVOKE] User not found: ${userId}`);
+      return { success: false, message: '用户不存在' };
+    }
+
+    // 2. 调用 blockchain-service 挂失助记词
+    try {
+      const result = await this.blockchainClient.revokeMnemonic(account.accountSequence.value, reason);
+      this.logger.log(`[REVOKE] Mnemonic revoke result: ${JSON.stringify(result)}`);
+      return result;
+    } catch (error) {
+      this.logger.error(`[REVOKE] Failed to revoke mnemonic`, error);
+      return { success: false, message: '挂失失败，请稍后重试' };
+    }
+  }
 }
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 070852e8..9fa63352 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
@@ -165,4 +165,30 @@ export class BlockchainClientService {
       throw error;
     }
   }
+
+  /**
+   * 挂失助记词
+   */
+  async revokeMnemonic(accountSequence: string, reason: string): Promise<{ success: boolean; message: string }> {
+    this.logger.log(`Revoking mnemonic for account ${accountSequence}, reason: ${reason}`);
+
+    try {
+      const response = await firstValueFrom(
+        this.httpService.post<{ success: boolean; message: string }>(
+          `${this.blockchainServiceUrl}/internal/mnemonic/revoke`,
+          { accountSequence, reason },
+          {
+            headers: { 'Content-Type': 'application/json' },
+            timeout: 30000,
+          },
+        ),
+      );
+
+      this.logger.log(`Mnemonic revoke result: success=${response.data.success}`);
+      return response.data;
+    } catch (error) {
+      this.logger.error('Failed to revoke mnemonic', error);
+      throw error;
+    }
+  }
 }