diff --git a/app/controllers/homework_common_controller.rb b/app/controllers/homework_common_controller.rb
index 49e6ec290..0d6a1a0e7 100644
--- a/app/controllers/homework_common_controller.rb
+++ b/app/controllers/homework_common_controller.rb
@@ -82,7 +82,7 @@ class HomeworkCommonController < ApplicationController
         homework_detail_manual.comment_status = 1
       end
       eval_start = homework_detail_manual.evaluation_start
-      if eval_start <= @homework.end_time && homework_detail_manual.comment_status <= 1
+      if eval_start.nil? || (eval_start <= @homework.end_time && homework_detail_manual.comment_status <= 1)
         homework_detail_manual.evaluation_start = @homework.end_time + 7
         homework_detail_manual.evaluation_end = homework_detail_manual.evaluation_start + 7
       end
diff --git a/app/views/users/_user_homework_detail.html.erb b/app/views/users/_user_homework_detail.html.erb
index 2b39f25a1..7af8ada43 100644
--- a/app/views/users/_user_homework_detail.html.erb
+++ b/app/views/users/_user_homework_detail.html.erb
@@ -71,7 +71,7 @@
           <%= user_for_homework_common homework_common,is_teacher %>
         </div>
         <% work = cur_user_works_for_homework homework_common %>
-        <% if homework_common.end_time < Date.today && !is_teacher && !work.nil? %>
+        <% if !is_teacher && !work.nil? && homework_common.end_time < Date.today %>
             <div class="homepagePostSubmit">
               <%=link_to "追加附件", student_work_index_url_in_org(homework_common.id, 1), :class => 'c_blue', :title => "可追加作品修订附件" %>
             </div>