diff --git a/app/api/mobile/apis/comments.rb b/app/api/mobile/apis/comments.rb
index 402bce66f..fb30f59f4 100644
--- a/app/api/mobile/apis/comments.rb
+++ b/app/api/mobile/apis/comments.rb
@@ -19,6 +19,25 @@ module Mobile
           present :status, 0
         end
 
+        desc '作业留言（教师布置的作业）'
+        params do
+          requires :token, type: String
+          requires :id, type: Integer,desc: '老师布置的作业id'
+          requires :message,type: String, desc: '留言'
+          optional :reference_content, type: String ,desc: '引用的内容'
+          optional :reference_user_id, type: Integer,desc: '被引用的人'
+        end
+        post 'create_homework_message' do
+          cs_params = {
+              id: params[:id],
+              token: params[:token],
+              reference_content: params[:reference_content],
+              bid_message: params.reject{|k,v| [:id,:token,:reference_content].include?(k)}}
+          cs = CommentService.new
+          cs.homework_message cs_params,current_user
+          present :status, 0
+        end
+
       end
     end
   end
diff --git a/app/services/comment_service.rb b/app/services/comment_service.rb
index c7e4b29a7..84a7d09cf 100644
--- a/app/services/comment_service.rb
+++ b/app/services/comment_service.rb
@@ -16,4 +16,24 @@ class CommentService
     @news.comments << @comment
     @comment
   end
+
+  #作业留言
+  def homework_message params,current_user
+    @bid = Bid.find(params[:id], :include => [{:homeworks => :user}])
+    if params[:bid_message][:message].size>0
+      if params[:reference_content]
+        message = params[:bid_message][:message] + "\n" + params[:reference_content]
+      else
+        message = params[:bid_message][:message]
+        @m = message
+      end
+      refer_user_id = params[:bid_message][:reference_user_id].to_i
+      @bid.add_jour(current_user, message, refer_user_id)
+    end
+    #@user = @bid.author
+    #@jours = @bid.journals_for_messages.where('m_parent_id IS NULL').order('created_on DESC')
+    #@jour = paginateHelper @jours,10
+    @bid.set_commit(@feedback_count)
+  end
+
 end
\ No newline at end of file
diff --git a/app/services/courses_service.rb b/app/services/courses_service.rb
index 77b5e325d..341ecd422 100644
--- a/app/services/courses_service.rb
+++ b/app/services/courses_service.rb
@@ -136,8 +136,6 @@ class CoursesService
       if current_user.nil? || !(current_user.admin? || @course.is_public == 1 || (@course.is_public == 0 && current_user.member_of_course?(@course)))
         raise '403'
       end
-    else
-      raise 'news in unknown course'
     end
     @comments = @news.comments
     @comments.reverse! if current_user.wants_comments_in_reverse_order?