diff --git a/app/controllers/wechats_controller.rb b/app/controllers/wechats_controller.rb
index f6e73e088..2cb114a56 100644
--- a/app/controllers/wechats_controller.rb
+++ b/app/controllers/wechats_controller.rb
@@ -183,7 +183,7 @@ class WechatsController < ActionController::Base
 
   def join_class(content, user)
     cs = CoursesService.new
-    status = cs.join_course({invite_code: content.trim}, current_user)
+    status = cs.join_course({invite_code: content.strip}, current_user)
     logger.info status
     status[:state] == 0 ? status[:course] : nil
   end