fix

app/helpers/welcome_helper.rb

@@ -20,6 +20,7 @@
 module WelcomeHelper
 
   include CoursesHelper
+  include ProjectsHelper
 
   def find_new_course limit=15
     Project.visible.joins(:course_extra).where("#{Project.table_name}.project_type = ? ", 1).order("courses.time DESC, #{Project.table_name}.created_on DESC").limit(limit).all

app/views/welcome/course.html.erb

@@ -125,7 +125,7 @@
 					<span style="cursor: pointer; display: inline-block; float: right; color: #ec6300; white-space: nowrap;">学生人数：<%= link_to "#{studentCount(project)}", project_member_path(project, :role => 2) ,:course =>'1', :target => "_blank" %></span>
 
 					<div id='join_in_course' style='margin: 0px 4px;display:inline-block;float:right;color:#ff4800;'>
-						<%if User.current.logged? %>
+						<%if User.current.logged? && !(course_timeout? project)%>
 						<%= join_in_course(project, User.current) unless project.course_extra.teacher.id == User.current.id %>
 						<% end %> 
 					</div>