diff --git a/app/models/course_activity.rb b/app/models/course_activity.rb
index 1b05e876d..02b6dacf1 100644
--- a/app/models/course_activity.rb
+++ b/app/models/course_activity.rb
@@ -1,7 +1,7 @@
 class CourseActivity < ActiveRecord::Base
   attr_accessible :user_id, :course_act_id,:course_act_type,:course_id
   # 虚拟关联
-  belongs_to :act ,:polymorphic => true
+  belongs_to :course_act ,:polymorphic => true
   belongs_to :course
   belongs_to :user
 end
diff --git a/db/migrate/20150811080754_course_activities.rb b/db/migrate/20150811080754_course_activities.rb
new file mode 100644
index 000000000..bdb8e19c0
--- /dev/null
+++ b/db/migrate/20150811080754_course_activities.rb
@@ -0,0 +1,39 @@
+#encoding=UTF-8
+class CourseActivities < ActiveRecord::Migration
+  def up
+    Course.all.each do |course|
+      transaction do
+        #作业
+        course.homework_commons.each do |homework_common|
+          homework_common.course_acts << CourseActivity.new(:user_id => homework_common.user_id,:course_id => course.id)
+        end
+        #通知
+        course.news.each do |new|
+          new.course_acts << CourseActivity.new(:user_id => new.author_id,:course_id => course.id)
+        end
+        #资源
+        course.attachments.each do |attachment|
+          attachment.course_acts << CourseActivity.new(:user_id => attachment.author_id,:course_id => course.id)
+        end
+        #讨论区
+        if course.boards.first
+          course.boards.first.messages.each do |message|
+            message.course_acts << CourseActivity.new(:user_id => message.author_id,:course_id => course.id)
+          end
+        end
+        #留言
+        course.journals_for_messages.each do |jour|
+          jour.course_acts << CourseActivity.new(:user_id => jour.user_id,:course_id => course.id)
+        end
+        #问卷
+        Poll.where("polls_type = 'Course' and polls_group_id = #{course.id}").each do |poll|
+          poll.course_acts << CourseActivity.new(:user_id => poll.user_id,:course_id => course.id)
+        end
+      end
+    end
+  end
+
+  def down
+    CourseActivity.destroy_all
+  end
+end
diff --git a/db/migrate/20150811083234_update_course_activity_time.rb b/db/migrate/20150811083234_update_course_activity_time.rb
new file mode 100644
index 000000000..9ba8140d8
--- /dev/null
+++ b/db/migrate/20150811083234_update_course_activity_time.rb
@@ -0,0 +1,22 @@
+class UpdateCourseActivityTime < ActiveRecord::Migration
+  def up
+    count = CourseActivity.all.count / 10 + 1
+    transaction do
+      for i in 1 ... count do i
+        CourseActivity.page(i).per(10).each do |activity|
+          if activity.course_act
+            if activity.course_act.respond_to?("created_at")
+              activity.created_at = activity.course_act.created_at
+            elsif activity.course_act.respond_to?("created_on")
+              activity.created_at = activity.course_act.created_on
+            end
+            activity.save
+          end
+        end
+      end
+    end
+  end
+
+  def down
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ac1bb987c..1488ca365 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20150811065543) do
+ActiveRecord::Schema.define(:version => 20150811083234) do
 
   create_table "activities", :force => true do |t|
     t.integer "act_id",                                  :null => false