diff --git a/app/controllers/zips_controller.rb b/app/controllers/zips_controller.rb
index 77a41d065..4de85ec64 100644
--- a/app/controllers/zips_controller.rb
+++ b/app/controllers/zips_controller.rb
@@ -17,7 +17,7 @@ class ZipsController < ApplicationController
   end
 
   def export_exercises
-    exercises = ExportExercisesService.new(@exercise,@ex_users,@request_url)
+    exercises = ExportExercisesService.new(@exercise,@ex_users)
 
     file_name = filename_for_content_disposition(exercises.filename)
     send_file exercises.ex_zip, filename: file_name, type: 'application/zip'
@@ -41,7 +41,6 @@ class ZipsController < ApplicationController
     ActiveRecord::Base.transaction do
       begin
         @exercise = Exercise.includes(:exercise_users,:exercise_questions).find_by(id:params[:exercise_id])
-        @request_url = request.base_url
         group_id = params[:exercise_group_id]
         if @exercise.blank?
           normal_status(-1,"试卷不存在")
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index e6bc84f20..f0cac79b9 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -334,6 +334,7 @@ module ApplicationHelper
     raw arr.join('')
   end
 
+  # 导出pdf时，转化markdown为html
   def to_markdown(text)
     request_url = request.base_url
 
diff --git a/app/services/exercise_user_pdf_service.rb b/app/services/exercise_user_pdf_service.rb
index 9b96cd70c..be048c4c2 100644
--- a/app/services/exercise_user_pdf_service.rb
+++ b/app/services/exercise_user_pdf_service.rb
@@ -5,10 +5,9 @@ class ExerciseUserPdfService
 
   attr_reader :exercise, :ex_user
 
-  def initialize(exercise, ex_user,request_url)
+  def initialize(exercise, ex_user)
     @exercise = exercise
     @ex_user = ex_user
-    @request_url = request_url
     @ex_user_user = @ex_user.user
     @course = @exercise.course
   end
diff --git a/app/services/export_exercises_service.rb b/app/services/export_exercises_service.rb
index 48bfc9519..12b5501f9 100644
--- a/app/services/export_exercises_service.rb
+++ b/app/services/export_exercises_service.rb
@@ -3,10 +3,9 @@ class ExportExercisesService
   include StudentWorksHelper
   attr_reader :exercise, :ex_users
 
-  def initialize(exercise, ex_users,request_url)
+  def initialize(exercise, ex_users)
     @exercise = exercise
     @ex_users = ex_users
-    @request_url = request_url
   end
 
   def filename
@@ -19,7 +18,7 @@ class ExportExercisesService
     pdfs = []
     Zip::File.open(zip_file.path, Zip::File::CREATE) do |zip|
       ex_users.each do |ex_user|
-        export = ExerciseUserPdfService.new(exercise, ex_user,@request_url)
+        export = ExerciseUserPdfService.new(exercise, ex_user)
         pdf = export.ex_pdf
         pdfs << pdf
         begin