diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index bf125972b..e3b2df048 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -474,11 +474,16 @@ module ApplicationHelper
   def principals_check_box_tags_ex(name, principals)
     s = ''
     principals.each do |principal|
-      if principal.has_attribute?(:userInfo)
-        s << "<label>#{ check_box_tag name, principal.id, false, :id => nil } #{h principal.userInfo }</label>\n"
-      else
-        s << "<label>#{ check_box_tag name, principal.id, false, :id => nil } #{h principal}</label>\n"
-      end
+      s << "<label>#{ check_box_tag name, principal.id, false, :id => nil } #{h principal.userInfo }</label>\n"
+    end
+    s.html_safe
+  end
+
+  #扩展的checkbox生成
+  def principals_radio_box_tags_ex(name, principals)
+    s = ''
+    principals.each do |principal|
+      s << "<label>#{ radio_button_tag name, principal.id, false, :id => nil } #{h principal.userInfo }</label>\n"
     end
     s.html_safe
   end
diff --git a/app/views/courses/settings/_members.html.erb b/app/views/courses/settings/_members.html.erb
index 0879b7956..b4e5004bf 100644
--- a/app/views/courses/settings/_members.html.erb
+++ b/app/views/courses/settings/_members.html.erb
@@ -32,7 +32,7 @@
 
                     <p>
                       <% roles.each do |role| %>
-                          <label><%= check_box_tag 'membership[role_ids][]', role.id, member.roles.include?(role),
+                          <label><%= radio_button_tag 'membership[role_ids][]', role.id, member.roles.include?(role),
                                                    :disabled => member.member_roles.detect { |mr| mr.role_id == role.id && !mr.inherited_from.nil? } %> <%= h role %></label><br/>
                       <% end %></p>
                     <%= hidden_field_tag 'membership[role_ids][]', '' %>
@@ -82,7 +82,7 @@
             <p style="padding-top: 5px"><%= l(:label_role_plural) %>:
               <% roles.each do |role| %>
 
-                  <label><%= check_box_tag 'membership[role_ids][]', role.id %> <%= h role %></label>
+                  <label><%= radio_button_tag 'membership[role_ids][]', role.id %> <%= h role %></label>
               <% end %></p>
 
             <p><%= submit_tag l(:button_add), :id => 'member-add-submit' %></p>