diff --git a/frontend/src/components/LoginModal.jsx b/frontend/src/components/LoginModal.jsx
index 49ee9cf..6fbaada 100644
--- a/frontend/src/components/LoginModal.jsx
+++ b/frontend/src/components/LoginModal.jsx
@@ -64,7 +64,7 @@ const LoginModal = ({ visible, onClose, onLoginSuccess }) => {
       open={visible}
       onCancel={onClose}
       footer={null}
-      destroyOnClose
+      destroyOnClose={true}
       centered
     >
       <Form
diff --git a/frontend/src/pages/activity/Detail.jsx b/frontend/src/pages/activity/Detail.jsx
index 6fb3dfd..97da7d3 100644
--- a/frontend/src/pages/activity/Detail.jsx
+++ b/frontend/src/pages/activity/Detail.jsx
@@ -9,12 +9,16 @@ import { message, Spin, Button, Result } from 'antd';
 import { getActivityDetail, signUpActivity } from '../../api';
 import styles from '../../components/activity/activity.module.less';
 import { pageTransition, buttonTap } from '../../animation';
+import LoginModal from '../../components/LoginModal';
+import { useAuth } from '../../context/AuthContext';
 
 const ActivityDetail = () => {
   const { id } = useParams();
   const navigate = useNavigate();
   const queryClient = useQueryClient();
   const { scrollY } = useScroll();
+  const { login } = useAuth();
+  const [loginVisible, setLoginVisible] = useState(false);
   
   // Header animation: transparent to white with shadow
   const headerBg = useTransform(scrollY, [0, 60], ['rgba(255,255,255,0)', 'rgba(255,255,255,1)']);
@@ -71,6 +75,11 @@ const ActivityDetail = () => {
   };
 
   const handleSignUp = () => {
+      if (!localStorage.getItem('token')) {
+          message.warning('请先登录后报名');
+          setLoginVisible(true);
+          return;
+      }
       signUpMutation.mutate();
   };