diff --git a/app/controllers/zipdown_controller.rb b/app/controllers/zipdown_controller.rb
index 777c0d8b7..653400cbe 100644
--- a/app/controllers/zipdown_controller.rb
+++ b/app/controllers/zipdown_controller.rb
@@ -75,7 +75,9 @@ class ZipdownController < ApplicationController
     # 得到每一个人所有文件打包的zip文件
     # 并将每一个人的zip打包为一个并返回路径
     user_zip_paths = homeattaches.map do |homeattach|
-      zip_homework_by_user homeattach
+      if homeattach.attachments.count > 0
+        zip_homework_by_user homeattach
+      end
     end
     zipping "#{Time.now.to_i}_#{bid.name}.zip", user_zip_paths, OUTPUT_FOLDER
 
diff --git a/app/views/bids/_homework_list.html.erb b/app/views/bids/_homework_list.html.erb
index 81c960781..b58f918df 100644
--- a/app/views/bids/_homework_list.html.erb
+++ b/app/views/bids/_homework_list.html.erb
@@ -8,7 +8,7 @@
 	<table width="100%" valign="center">
 		<tr>
 			<td ><span style="margin-left:0px"><%= l(:label_task_plural)%>(<%= @homework_list.count%>)</span>
-        <%#= link_to "作业打包下载", zipdown_assort_path(obj_class: @bid.class, obj_id: @bid), remote: false, class: "button_submit button_submit_font_white", style: "margin: 5px 10px;line-height: 20px;height: 20px;display: inline-block;" if(is_teacher) %>
+        <%= link_to "作业打包下载", zipdown_assort_path(obj_class: @bid.class, obj_id: @bid), remote: false, class: "button_submit button_submit_font_white", style: "margin: 5px 10px;line-height: 20px;height: 20px;display: inline-block;" if(is_teacher && @bid.homeworks.count > 0) %>
             </td>
             <td align="right">
                 <div class="project-search">
diff --git a/db/migrate/20140722024513_update_course_attachment.rb b/db/migrate/20140722024513_update_course_attachment.rb
new file mode 100644
index 000000000..6b0372b5b
--- /dev/null
+++ b/db/migrate/20140722024513_update_course_attachment.rb
@@ -0,0 +1,20 @@
+class UpdateCourseAttachment < ActiveRecord::Migration
+  # 更新课程资源类型
+  def up
+    Attachment.all.each do |attachment|
+      if attachment.container_type == 'Course'
+        if attachment.attachtype == 1
+          attachment.attachtype = 4
+        elsif attachment.attachtype == 2
+          attachment.attachtype = 5
+        elsif attachment.attachtype == 3
+          attachment.attachtype = 6
+        end
+        attachment.save
+      end
+    end
+  end
+
+  def down
+  end
+end