diff --git a/app/helpers/users_helper.rb b/app/helpers/users_helper.rb
index d4f9e4eb8..558be15e2 100644
--- a/app/helpers/users_helper.rb
+++ b/app/helpers/users_helper.rb
@@ -335,7 +335,7 @@ module UsersHelper
     return Course.where("tea_id = ?",user.id).count()
   end
   def get_join_course_count(user)
-    return user.coursememberships.count() - get_create_course_count(user)
+    ((user.coursememberships.count() - get_create_course_count(user)) < 0) ? 0 : user.coursememberships.count() - get_create_course_count(user)
   end
   def get_homework_commons_count(user)
     return HomeworkCommon.where("user_id = ?",user.id).count()