diff --git a/app/controllers/exercise_controller.rb b/app/controllers/exercise_controller.rb
index a48298a83..18248331c 100644
--- a/app/controllers/exercise_controller.rb
+++ b/app/controllers/exercise_controller.rb
@@ -213,6 +213,10 @@ class ExerciseController < ApplicationController
     # 更新标准答案
     if params[:exercise_choice]
       if @exercise_question.question_type == 3
+        # 删除不合理的选项
+        @exercise_question.exercise_standard_answers.each do |answer|
+          answer.destroy unless params[:exercise_choice].keys.include? answer.id.to_s
+        end
         for i in 1..params[:exercise_choice].count
           # 找到对应的标准答案
           question_standart = @exercise_question.exercise_standard_answers.find_by_id params[:exercise_choice].keys[i-1]