diff --git a/backend/community/admin.py b/backend/community/admin.py
index 530fd6c..d0b571c 100644
--- a/backend/community/admin.py
+++ b/backend/community/admin.py
@@ -5,6 +5,7 @@ from django.shortcuts import redirect
 from unfold.admin import ModelAdmin, TabularInline
 from unfold.decorators import display
 from .models import Activity, ActivitySignup, Topic, Reply, TopicMedia, Announcement
+from .admin_actions import export_signups_csv, export_signups_excel
 
 class ActivitySignupInline(TabularInline):
     model = ActivitySignup
@@ -156,6 +157,7 @@ class ActivitySignupAdmin(ModelAdmin):
     list_filter = ('status', 'signup_time', 'activity')
     search_fields = ('user__nickname', 'activity__title')
     autocomplete_fields = ['activity', 'user']
+    actions = [export_signups_csv, export_signups_excel]
     
     fieldsets = (
         ('报名详情', {
diff --git a/backend/community/admin_actions.py b/backend/community/admin_actions.py
new file mode 100644
index 0000000..72146c8
--- /dev/null
+++ b/backend/community/admin_actions.py
@@ -0,0 +1,149 @@
+import csv
+import json
+import datetime
+from django.http import HttpResponse
+from django.utils.encoding import escape_uri_path
+
+def flatten_json(y):
+    """
+    Flatten a nested json object
+    """
+    out = {}
+
+    def flatten(x, name=''):
+        if type(x) is dict:
+            for a in x:
+                flatten(x[a], name + a + '_')
+        elif type(x) is list:
+            i = 0
+            for a in x:
+                flatten(a, name + str(i) + '_')
+                i += 1
+        else:
+            out[name[:-1]] = x
+
+    flatten(y)
+    return out
+
+def get_signup_info_keys(queryset):
+    """
+    Collect all unique keys from the signup_info JSON across the queryset
+    """
+    keys = set()
+    for obj in queryset:
+        if obj.signup_info and isinstance(obj.signup_info, dict):
+            # Flatten the dictionary first to get all nested keys
+            flat_info = flatten_json(obj.signup_info)
+            keys.update(flat_info.keys())
+    return sorted(list(keys))
+
+def export_signups_csv(modeladmin, request, queryset):
+    """
+    Export selected signups to CSV, including flattened JSON fields
+    """
+    opts = modeladmin.model._meta
+    filename = f"{opts.verbose_name}_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
+    
+    response = HttpResponse(content_type='text/csv; charset=utf-8-sig')
+    response['Content-Disposition'] = f'attachment; filename={escape_uri_path(filename)}'
+    
+    writer = csv.writer(response)
+    
+    # Base fields to export
+    base_headers = ['ID', '活动标题', '用户昵称', '用户ID', '报名时间', '状态', '关联订单ID']
+    
+    # Get dynamic JSON keys
+    json_keys = get_signup_info_keys(queryset)
+    
+    # Write header
+    writer.writerow(base_headers + json_keys)
+    
+    # Write data
+    for obj in queryset:
+        row = [
+            str(obj.id),
+            obj.activity.title,
+            obj.user.nickname if obj.user else 'Unknown',
+            str(obj.user.id) if obj.user else '',
+            obj.signup_time.strftime('%Y-%m-%d %H:%M:%S'),
+            obj.get_status_display(),
+            str(obj.order.id) if obj.order else ''
+        ]
+        
+        # Add JSON data
+        flat_info = {}
+        if obj.signup_info and isinstance(obj.signup_info, dict):
+            flat_info = flatten_json(obj.signup_info)
+            
+        for key in json_keys:
+            val = flat_info.get(key, '')
+            if val is None:
+                val = ''
+            row.append(str(val))
+            
+        writer.writerow(row)
+        
+    return response
+
+export_signups_csv.short_description = "导出选中报名记录为 CSV (含详细信息)"
+
+def export_signups_excel(modeladmin, request, queryset):
+    """
+    Export selected signups to Excel, including flattened JSON fields
+    """
+    try:
+        from openpyxl import Workbook
+    except ImportError:
+        modeladmin.message_user(request, "请先安装 openpyxl 库以使用 Excel 导出功能", level='error')
+        return
+
+    opts = modeladmin.model._meta
+    filename = f"{opts.verbose_name}_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.xlsx"
+    
+    response = HttpResponse(
+        content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+    )
+    response['Content-Disposition'] = f'attachment; filename={escape_uri_path(filename)}'
+    
+    wb = Workbook()
+    ws = wb.active
+    ws.title = str(opts.verbose_name)[:31]  # Sheet name limit is 31 chars
+    
+    # Base fields to export
+    base_headers = ['ID', '活动标题', '用户昵称', '用户ID', '报名时间', '状态', '关联订单ID']
+    
+    # Get dynamic JSON keys
+    json_keys = get_signup_info_keys(queryset)
+    
+    # Write header
+    ws.append(base_headers + json_keys)
+    
+    # Write data
+    for obj in queryset:
+        row = [
+            obj.id,
+            obj.activity.title,
+            obj.user.nickname if obj.user else 'Unknown',
+            obj.user.id if obj.user else '',
+            obj.signup_time.replace(tzinfo=None) if obj.signup_time else '', # Remove tz for Excel
+            obj.get_status_display(),
+            obj.order.id if obj.order else ''
+        ]
+        
+        # Add JSON data
+        flat_info = {}
+        if obj.signup_info and isinstance(obj.signup_info, dict):
+            flat_info = flatten_json(obj.signup_info)
+            
+        for key in json_keys:
+            val = flat_info.get(key, '')
+            if val is None:
+                val = ''
+            row.append(str(val)) # Ensure string for simplicity, or handle types
+            
+        ws.append(row)
+        
+    wb.save(response)
+    return response
+
+export_signups_excel.short_description = "导出选中报名记录为 Excel (含详细信息)"
diff --git a/backend/shop/views.py b/backend/shop/views.py
index 90d71cb..9131719 100644
--- a/backend/shop/views.py
+++ b/backend/shop/views.py
@@ -1136,16 +1136,17 @@ def wechat_login(request):
             
             else:
                 # 【新建场景】: 都不存在 -> 创建新用户
-                user = WeChatUser.objects.create(openid=openid)
                 if phone_number:
+                    user = WeChatUser.objects.create(openid=openid)
                     user.phone_number = phone_number
                     user.save()
+                else:
+                    # 如果没有手机号（静默登录），不自动创建新用户
+                    print(f"未注册用户尝试静默登录: OpenID={openid}")
+                    pass
 
-            # 统一更新会话信息 (确保 user 对象是最新的)
-            # 重新获取对象以防状态不一致 (可选，但推荐)
-            # user.refresh_from_db() 
-            
-            if user.openid == openid:
+            # 统一更新会话信息 (确保 user 对象存在)
+            if user and user.openid == openid:
                 user.session_key = session_key
                 user.unionid = unionid
                 
@@ -1189,7 +1190,8 @@ def wechat_login(request):
 
     # 生成 Token
     if not user:
-         return Response({'error': 'Login failed: User not created'}, status=500)
+         # 用户未注册且未提供手机号
+         return Response({'error': 'User not registered', 'code': 'USER_NOT_FOUND'}, status=404)
 
     signer = TimestampSigner()
     token = signer.sign(user.openid)
diff --git a/miniprogram/src/app.ts b/miniprogram/src/app.ts
index dd997ff..8791ab6 100644
--- a/miniprogram/src/app.ts
+++ b/miniprogram/src/app.ts
@@ -26,12 +26,23 @@ function App({ children }: PropsWithChildren<any>) {
         }
     }
 
-    // Auto login
-    login().then(res => {
-        console.log('Logged in as:', res?.nickname)
-    }).catch(err => {
-        console.log('Auto login failed', err)
-    })
+    // Auto login only if user info with phone number exists
+    const userInfo = Taro.getStorageSync('userInfo')
+    if (userInfo && userInfo.phone_number) {
+        console.log('User has phone number, attempting auto login...')
+        login().then(res => {
+           console.log('Auto login success, user:', res?.nickname)
+        }).catch(err => {
+           console.log('Auto login failed', err)
+           // If login fails (e.g. user deleted on backend), clear storage
+           if (err.statusCode === 404 || err.statusCode === 401) {
+               Taro.removeStorageSync('userInfo')
+               Taro.removeStorageSync('token')
+           }
+        })
+    } else {
+        console.log('No phone number found, skipping auto login')
+    }
   })
 
   return children