diff --git a/backend-java/src/main/java/com/nanri/aiimage/modules/auth/service/AuthService.java b/backend-java/src/main/java/com/nanri/aiimage/modules/auth/service/AuthService.java
index bd252cd5..e6464356 100644
--- a/backend-java/src/main/java/com/nanri/aiimage/modules/auth/service/AuthService.java
+++ b/backend-java/src/main/java/com/nanri/aiimage/modules/auth/service/AuthService.java
@@ -56,20 +56,19 @@ public class AuthService {
             stored = deviceId;
             log.info("[auth] first-login bind userId={} device={}", user.getId(), deviceId);
         } else if (!stored.equals(deviceId)) {
-            if (isAdmin) {
-                log.warn("[auth] device mismatch but admin bypass userId={} stored={} current={}",
-                        user.getId(), stored, deviceId);
-            } else {
-                log.warn("[auth] device mismatch reject userId={} stored={} current={}",
-                        user.getId(), stored, deviceId);
-                throw new BusinessException("当前设备与首次登录设备不一致，请在原设备上登录");
-            }
+            // 设备指纹变化(换电脑/重装/清理注册表)会锁死账号，密码已验证通过，
+            // 直接重新绑定到当前设备，避免账号被锁、数据因重建账号而丢失。
+            loginUserMapper.update(null, new LambdaUpdateWrapper<LoginUserEntity>()
+                    .eq(LoginUserEntity::getId, user.getId())
+                    .set(LoginUserEntity::getMachine, deviceId));
+            log.warn("[auth] device rebound on login userId={} old={} new={}",
+                    user.getId(), stored, deviceId);
         } else {
             log.info("[auth] device match userId={} isAdmin={} device={}",
                     user.getId(), isAdmin, deviceId);
         }
 
-        return buildResult(user, stored, isAdmin);
+        return buildResult(user, deviceId, isAdmin);
     }
 
     public LoginResultVo checkLogin(String token, String currentDeviceId) {