diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 38c2b9e90..0c8be7b84 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -59,9 +59,15 @@ module ApplicationHelper
   end
 
   # 获取项/课程 news最新列表
-  # params course ID or project ID
-  def news_act_order
-
+  # params course: course ID or project ID
+  def news_act_order(course)
+    a = []
+    course.news.each do |new|
+      unless new.comments.blank?
+        new = new.comments.sort! { |a,b| a.created_on <=> b.created_on}.last.commented
+      end
+      a << new
+    end
   end
 
   # Time 2015-03-24 16:38:05