diff --git a/src/core/register.py b/src/core/register.py
index 4fa3215..6fdafaa 100644
--- a/src/core/register.py
+++ b/src/core/register.py
@@ -297,7 +297,23 @@ class RegistrationEngine:
             self._log(f"提交密码状态: {response.status_code}")
 
             if response.status_code != 200:
-                self._log(f"密码注册失败: {response.text[:200]}", "warning")
+                error_text = response.text[:500]
+                self._log(f"密码注册失败: {error_text}", "warning")
+
+                # 解析错误信息，判断是否是邮箱已注册
+                try:
+                    error_json = response.json()
+                    error_msg = error_json.get("error", {}).get("message", "")
+                    error_code = error_json.get("error", {}).get("code", "")
+
+                    # 检测邮箱已注册的情况
+                    if "already" in error_msg.lower() or "exists" in error_msg.lower() or error_code == "user_exists":
+                        self._log(f"邮箱 {self.email} 可能已在 OpenAI 注册过", "error")
+                        # 标记此邮箱为已注册状态
+                        self._mark_email_as_registered()
+                except Exception:
+                    pass
+
                 return False, None
 
             return True, password
@@ -306,6 +322,27 @@ class RegistrationEngine:
             self._log(f"密码注册失败: {e}", "error")
             return False, None
 
+    def _mark_email_as_registered(self):
+        """标记邮箱为已注册状态（用于防止重复尝试）"""
+        try:
+            with get_db() as db:
+                # 检查是否已存在该邮箱的记录
+                existing = crud.get_account_by_email(db, self.email)
+                if not existing:
+                    # 创建一个失败记录，标记该邮箱已注册过
+                    crud.create_account(
+                        db,
+                        email=self.email,
+                        password="",  # 空密码表示未成功注册
+                        email_service=self.email_service.service_type.value,
+                        email_service_id=self.email_info.get("service_id") if self.email_info else None,
+                        status="failed",
+                        extra_data={"register_failed_reason": "email_already_registered_on_openai"}
+                    )
+                    self._log(f"已在数据库中标记邮箱 {self.email} 为已注册状态")
+        except Exception as e:
+            logger.warning(f"标记邮箱状态失败: {e}")
+
     def _send_verification_code(self) -> bool:
         """发送验证码"""
         try:
diff --git a/src/database/crud.py b/src/database/crud.py
index 1af726b..79fef2a 100644
--- a/src/database/crud.py
+++ b/src/database/crud.py
@@ -29,7 +29,8 @@ def create_account(
     id_token: Optional[str] = None,
     proxy_used: Optional[str] = None,
     expires_at: Optional['datetime'] = None,
-    extra_data: Optional[Dict[str, Any]] = None
+    extra_data: Optional[Dict[str, Any]] = None,
+    status: Optional[str] = None
 ) -> Account:
     """创建新账户"""
     db_account = Account(
@@ -47,6 +48,7 @@ def create_account(
         proxy_used=proxy_used,
         expires_at=expires_at,
         extra_data=extra_data or {},
+        status=status or 'active',
         registered_at=datetime.utcnow()
     )
     db.add(db_account)
diff --git a/src/web/routes/registration.py b/src/web/routes/registration.py
index a8f6db3..ff6ced7 100644
--- a/src/web/routes/registration.py
+++ b/src/web/routes/registration.py
@@ -248,18 +248,37 @@ async def run_registration_task(task_uuid: str, email_service_type: str, proxy:
                         raise ValueError("没有可用的自定义域名邮箱服务，请先在设置中配置")
                 elif service_type == EmailServiceType.OUTLOOK:
                     # 检查数据库中是否有可用的 Outlook 账户
-                    from ...database.models import EmailService as EmailServiceModel
-                    db_service = db.query(EmailServiceModel).filter(
+                    from ...database.models import EmailService as EmailServiceModel, Account
+                    # 获取所有启用的 Outlook 服务
+                    outlook_services = db.query(EmailServiceModel).filter(
                         EmailServiceModel.service_type == "outlook",
                         EmailServiceModel.enabled == True
-                    ).order_by(EmailServiceModel.priority.asc()).first()
+                    ).order_by(EmailServiceModel.priority.asc()).all()
 
-                    if db_service and db_service.config:
-                        config = db_service.config.copy()
-                        crud.update_registration_task(db, task_uuid, email_service_id=db_service.id)
-                        logger.info(f"使用数据库 Outlook 账户: {db_service.name}")
-                    else:
+                    if not outlook_services:
                         raise ValueError("没有可用的 Outlook 账户，请先在设置中导入账户")
+
+                    # 找到一个未注册的 Outlook 账户
+                    selected_service = None
+                    for svc in outlook_services:
+                        email = svc.config.get("email") if svc.config else None
+                        if not email:
+                            continue
+                        # 检查是否已在 accounts 表中注册
+                        existing = db.query(Account).filter(Account.email == email).first()
+                        if not existing:
+                            selected_service = svc
+                            logger.info(f"选择未注册的 Outlook 账户: {email}")
+                            break
+                        else:
+                            logger.info(f"跳过已注册的 Outlook 账户: {email}")
+
+                    if selected_service and selected_service.config:
+                        config = selected_service.config.copy()
+                        crud.update_registration_task(db, task_uuid, email_service_id=selected_service.id)
+                        logger.info(f"使用数据库 Outlook 账户: {selected_service.name}")
+                    else:
+                        raise ValueError("所有 Outlook 账户都已注册过 OpenAI 账号，请添加新的 Outlook 账户")
                 else:
                     config = email_service_config or {}