diff --git a/app/models/course.rb b/app/models/course.rb
index 79b8c068..796ea3c9 100644
--- a/app/models/course.rb
+++ b/app/models/course.rb
@@ -177,7 +177,7 @@ class Course < ActiveRecord::Base
   end
 
   def member_count
-    Member.find_by_sql("select count(id) as count from members where course_id=#{self.id}").first.try(:count).to_i
+    CourseMember.find_by_sql("select count(id) as count from course_members where course_id=#{self.id}").first.try(:count).to_i
   end
 
   def self.search(query)
@@ -257,7 +257,7 @@ class Course < ActiveRecord::Base
 
   # 选出教师数不为0的答辩组
   def course_graduation_group
-    self.graduation_groups.select{|group| group.members.count > 0}
+    self.graduation_groups.select{|group| group.course_members.count > 0}
   end
 
   # 课程的短描述信息
@@ -420,11 +420,12 @@ class Course < ActiveRecord::Base
 
   # 删除课程所有成员
   def delete_all_members
-    if self.members && self.members.count > 0
-      me, mr = Member.table_name, MemberRole.table_name
-      connection.delete("DELETE FROM #{mr} WHERE #{mr}.member_id IN (SELECT #{me}.id FROM #{me} WHERE #{me}.course_id = #{id})")
-      Member.delete_all(['course_id = ?', id])
-    end
+    CourseMember.delete_all(['course_id = ?', id])
+    # if self.members && self.members.count > 0
+    #   me, mr = Member.table_name, MemberRole.table_name
+    #   connection.delete("DELETE FROM #{mr} WHERE #{mr}.member_id IN (SELECT #{me}.id FROM #{me} WHERE #{me}.course_id = #{id})")
+    #   Member.delete_all(['course_id = ?', id])
+    # end
   end
 
   # 创建课程模块
diff --git a/app/models/graduation_group.rb b/app/models/graduation_group.rb
index 12570681..f0cd21e7 100644
--- a/app/models/graduation_group.rb
+++ b/app/models/graduation_group.rb
@@ -2,6 +2,7 @@ class GraduationGroup < ActiveRecord::Base
   belongs_to :course
   belongs_to :user
   has_many :members
+  has_many :course_members
   has_one :graduation_task_group_assignation, dependent: :destroy
   has_many :graduation_work_comment_assignations, dependent: :destroy
   attr_accessible :name, :user_id, :course_id