diff --git a/app/jobs/homework_evaluation_comment_assgin_job.rb b/app/jobs/homework_evaluation_comment_assgin_job.rb
index 2579ea18b..5921386f2 100644
--- a/app/jobs/homework_evaluation_comment_assgin_job.rb
+++ b/app/jobs/homework_evaluation_comment_assgin_job.rb
@@ -16,7 +16,7 @@ class HomeworkEvaluationCommentAssginJob < ApplicationJob
       student_work_projects = homework_common.student_works.where("work_status != 0").shuffle
       student_work_projects.each do |pro_work|
         n = homework_detail_manual.evaluation_num
-        n = (n < student_works.size && n != -1) ? n : student_works.size - 1
+        n = (n < student_works.length && n != -1) ? n : student_works.length - 1
         work_index = -1
         student_works.each_with_index do |stu_work, stu_index|
           if stu_work.group_id.to_i == pro_work.group_id.to_i