diff --git a/backend/services/auth-service/src/application/services/auth.service.ts b/backend/services/auth-service/src/application/services/auth.service.ts
index 44f8a08..960ec70 100644
--- a/backend/services/auth-service/src/application/services/auth.service.ts
+++ b/backend/services/auth-service/src/application/services/auth.service.ts
@@ -113,7 +113,14 @@ export class AuthService {
   /* ── Password Login ── */
 
   async login(dto: LoginDto): Promise<AuthResult> {
-    const user = await this.userRepo.findByPhoneOrEmail(dto.identifier);
+    // Normalize phone numbers to E.164 before lookup (e.g. 18926762721 → +8618926762721)
+    let identifier = dto.identifier;
+    try {
+      identifier = Phone.create(dto.identifier).value;
+    } catch {
+      // Not a valid phone number — treat as email, use as-is
+    }
+    const user = await this.userRepo.findByPhoneOrEmail(identifier);
     if (!user) {
       throw new UnauthorizedException('账号或密码错误');
     }