diff --git a/db/migrate/20190314080802_create_shixun_student_works.rb b/db/migrate/20190314080802_create_shixun_student_works.rb
index 240adc00..49106739 100644
--- a/db/migrate/20190314080802_create_shixun_student_works.rb
+++ b/db/migrate/20190314080802_create_shixun_student_works.rb
@@ -24,49 +24,52 @@ class CreateShixunStudentWorks < ActiveRecord::Migration
           shixun = work.homework_common.try(:homework_commons_shixuns).try(:shixun)
           user = work.user
           if shixun.present? && user.present?
-            # 创建新的myshixun和games
-            # fork版本库，如果用户没有同步，则先同步用户
-            g = Gitlab.client
-            if user.gid.nil?
-              s = Trustie::Gitlab::Sync.new
-              s.sync_user(user)
-            end
-            gshixun = g.fork(shixun.gpid, user.gid)
-            shixun_tomcat = Redmine::Configuration['shixun_tomcat']
+            myshixun = Myshixun.where(:user_id => user.id, :shixun_id => shixun.id).first
+            if myshixun.blank?
+              # 创建新的myshixun和games
+              # fork版本库，如果用户没有同步，则先同步用户
+              g = Gitlab.client
+              if user.gid.nil?
+                s = Trustie::Gitlab::Sync.new
+                s.sync_user(user)
+              end
+              gshixun = g.fork(shixun.gpid, user.gid)
+              shixun_tomcat = Redmine::Configuration['shixun_tomcat']
 
-            code = down_generate_identifier("myshixun")
-            # 一般通过默认分支是否存在来判断一个项目是否fork成功
-            if gshixun.try(:id).present?
-              commit_id = g.commits(shixun.gpid).first.try(:id)
-              # educoder 加入到myshixun中
-              myshixun_admin_gid = User.where(:login => "educoder").first.try(:gid)
-              g.add_team_member(gshixun.id, myshixun_admin_gid, 40)  # 40代表角色master
+              code = down_generate_identifier("myshixun")
+              # 一般通过默认分支是否存在来判断一个项目是否fork成功
+              if gshixun.try(:id).present?
+                commit_id = g.commits(shixun.gpid).first.try(:id)
+                # educoder 加入到myshixun中
+                myshixun_admin_gid = User.where(:login => "educoder").first.try(:gid)
+                g.add_team_member(gshixun.id, myshixun_admin_gid, 40)  # 40代表角色master
 
-              myshixun = Myshixun.create!(:shixun_id => shixun.id, :user_id => user.id, :identifier => code,
-                                          :modify_time => shixun.modify_time, :reset_time => shixun.reset_time,
-                                          :onclick_time => Time.now, :gpid => gshixun.id,
-                                          :git_url => gshixun.try(:path_with_namespace), :commit_id => commit_id)
+                myshixun = Myshixun.create!(:shixun_id => shixun.id, :user_id => user.id, :identifier => code,
+                                            :modify_time => shixun.modify_time, :reset_time => shixun.reset_time,
+                                            :onclick_time => Time.now, :gpid => gshixun.id,
+                                            :git_url => gshixun.try(:path_with_namespace), :commit_id => commit_id)
 
-              url = "#{Redmine::Configuration['gitlab_address_ip']}/#{g.project(shixun.try(:gpid)).try(:path_with_namespace)}.git"
+                url = "#{Redmine::Configuration['gitlab_address_ip']}/#{g.project(shixun.try(:gpid)).try(:path_with_namespace)}.git"
 
-              rep_url = Base64.urlsafe_encode64(url) # 注意：educoder为默认给实训创建版本库的用户，如果换成别的用户，名字要相应的修改
-              uri = "#{shixun_tomcat}/bridge/game/openGameInstance"
-              params = {tpiID: "#{myshixun.id}", tpmGitURL:rep_url, tpiRepoName: gshixun.try(:name)}
-              logger.info("openGameInstance params is #{params}")
-              uri = URI.parse(URI.encode(uri.strip))
-              res = Net::HTTP.post_form(uri, params).body
-              res = JSON.parse(res)
-              if (res && res['code'].to_i != 0)
-                raise("实训云平台繁忙（繁忙等级：83）")
-              end
-              # 其它创建关卡等操作
-              challenges = shixun.challenges
-              # 之所以增加user_id是为了方便统计查询性能
-              challenges.each_with_index do |challenge, index|
-                status = (index == 0 ? 0 : 3)
-                code = down_generate_identifier("game")
-                Game.create!(:challenge_id => challenge.id, :myshixun_id => myshixun.id, :status => status, :user_id => myshixun.user_id,
-                             :open_time => Time.now, :identifier => code, :modify_time => challenge.modify_time)
+                rep_url = Base64.urlsafe_encode64(url) # 注意：educoder为默认给实训创建版本库的用户，如果换成别的用户，名字要相应的修改
+                uri = "#{shixun_tomcat}/bridge/game/openGameInstance"
+                params = {tpiID: "#{myshixun.id}", tpmGitURL:rep_url, tpiRepoName: gshixun.try(:name)}
+                logger.info("openGameInstance params is #{params}")
+                uri = URI.parse(URI.encode(uri.strip))
+                res = Net::HTTP.post_form(uri, params).body
+                res = JSON.parse(res)
+                if (res && res['code'].to_i != 0)
+                  raise("实训云平台繁忙（繁忙等级：83）")
+                end
+                # 其它创建关卡等操作
+                challenges = shixun.challenges
+                # 之所以增加user_id是为了方便统计查询性能
+                challenges.each_with_index do |challenge, index|
+                  status = (index == 0 ? 0 : 3)
+                  code = down_generate_identifier("game")
+                  Game.create!(:challenge_id => challenge.id, :myshixun_id => myshixun.id, :status => status, :user_id => myshixun.user_id,
+                               :open_time => Time.now, :identifier => code, :modify_time => challenge.modify_time)
+                end
               end
               work_score = work.final_score
               work.homework_common.homework_challenge_settings.each do |setting|