diff --git a/backend/services/mining-admin-service/prisma/migrations/20260310_audit_log_nullable_admin/migration.sql b/backend/services/mining-admin-service/prisma/migrations/20260310_audit_log_nullable_admin/migration.sql
new file mode 100644
index 00000000..0a1a0204
--- /dev/null
+++ b/backend/services/mining-admin-service/prisma/migrations/20260310_audit_log_nullable_admin/migration.sql
@@ -0,0 +1,2 @@
+-- Make adminId nullable in audit_logs to support LOGIN_FAILED records without a valid admin account
+ALTER TABLE "audit_logs" ALTER COLUMN "admin_id" DROP NOT NULL;
diff --git a/backend/services/mining-admin-service/prisma/schema.prisma b/backend/services/mining-admin-service/prisma/schema.prisma
index 96bf5048..c9bdaad3 100644
--- a/backend/services/mining-admin-service/prisma/schema.prisma
+++ b/backend/services/mining-admin-service/prisma/schema.prisma
@@ -85,8 +85,8 @@ model InitializationRecord {
 
 model AuditLog {
   id          String   @id @default(uuid())
-  adminId     String
-  action      String   // CREATE, UPDATE, DELETE, LOGIN, LOGOUT, INIT
+  adminId     String?
+  action      String   // CREATE, UPDATE, DELETE, LOGIN, LOGIN_FAILED, LOGOUT, INIT
   resource    String   // CONFIG, USER, SYSTEM_ACCOUNT, MINING
   resourceId  String?
   oldValue    Json?
@@ -95,7 +95,7 @@ model AuditLog {
   userAgent   String?
   createdAt   DateTime @default(now())
 
-  admin       AdminUser @relation(fields: [adminId], references: [id])
+  admin       AdminUser? @relation(fields: [adminId], references: [id])
 
   @@index([adminId])
   @@index([action])
diff --git a/backend/services/mining-admin-service/src/application/services/auth.service.ts b/backend/services/mining-admin-service/src/application/services/auth.service.ts
index 8ddb080d..cee458c6 100644
--- a/backend/services/mining-admin-service/src/application/services/auth.service.ts
+++ b/backend/services/mining-admin-service/src/application/services/auth.service.ts
@@ -23,11 +23,17 @@ export class AuthService {
   async login(username: string, password: string, ipAddress?: string, userAgent?: string): Promise<{ token: string; admin: any }> {
     const admin = await this.prisma.adminUser.findUnique({ where: { username } });
     if (!admin || admin.status !== 'ACTIVE') {
+      await this.prisma.auditLog.create({
+        data: { action: 'LOGIN_FAILED', resource: 'AUTH', resourceId: username, newValue: { reason: admin ? 'account_disabled' : 'user_not_found' }, ipAddress, userAgent },
+      });
       throw new UnauthorizedException('Invalid credentials');
     }
 
     const isValid = await bcrypt.compare(password, admin.password);
     if (!isValid) {
+      await this.prisma.auditLog.create({
+        data: { adminId: admin.id, action: 'LOGIN_FAILED', resource: 'AUTH', resourceId: username, newValue: { reason: 'wrong_password' }, ipAddress, userAgent },
+      });
       throw new UnauthorizedException('Invalid credentials');
     }
 
diff --git a/frontend/mining-admin-web/src/app/(dashboard)/audit-logs/page.tsx b/frontend/mining-admin-web/src/app/(dashboard)/audit-logs/page.tsx
index 33784a84..9f7951a0 100644
--- a/frontend/mining-admin-web/src/app/(dashboard)/audit-logs/page.tsx
+++ b/frontend/mining-admin-web/src/app/(dashboard)/audit-logs/page.tsx
@@ -30,8 +30,9 @@ const actionLabels: Record<string, { label: string; className: string }> = {
   CREATE:     { label: '创建',   className: 'bg-green-100 text-green-700' },
   UPDATE:     { label: '更新',   className: 'bg-blue-100 text-blue-700' },
   DELETE:     { label: '删除',   className: 'bg-red-100 text-red-700' },
-  LOGIN:      { label: '登录',   className: 'bg-purple-100 text-purple-700' },
-  LOGOUT:     { label: '登出',   className: 'bg-gray-100 text-gray-600' },
+  LOGIN:        { label: '登录',     className: 'bg-purple-100 text-purple-700' },
+  LOGIN_FAILED: { label: '登录失败', className: 'bg-red-100 text-red-700' },
+  LOGOUT:       { label: '登出',     className: 'bg-gray-100 text-gray-600' },
   ENABLE:     { label: '启用',   className: 'bg-emerald-100 text-emerald-700' },
   DISABLE:    { label: '禁用',   className: 'bg-orange-100 text-orange-700' },
   UNLOCK:     { label: '解锁',   className: 'bg-yellow-100 text-yellow-700' },
@@ -93,6 +94,7 @@ export default function AuditLogsPage() {
               <SelectContent>
                 <SelectItem value="all">全部</SelectItem>
                 <SelectItem value="LOGIN">登录</SelectItem>
+                <SelectItem value="LOGIN_FAILED">登录失败</SelectItem>
                 <SelectItem value="LOGOUT">登出</SelectItem>
                 <SelectItem value="CREATE">创建</SelectItem>
                 <SelectItem value="UPDATE">更新</SelectItem>