diff --git a/contest/decorators.py b/contest/decorators.py
index 2f5e3ba..93e24fa 100644
--- a/contest/decorators.py
+++ b/contest/decorators.py
@@ -91,6 +91,10 @@ def check_user_contest_permission(func):
                 return render(request, "oj/contest/no_contest_permission.html",
                               {"reason": "contest_not_start", "show_tab": False, "contest": contest})
 
+        # 比赛已经结束了，只拦截 ajax 的答案提交
+        if contest.status == CONTEST_ENDED and request.is_ajax():
+            return error_response(u"比赛已经结束")
+
         return func(*args, **kwargs)
 
     return _check_user_contest_permission