diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index a5ff44417..8544b2cf3 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -1931,7 +1931,7 @@ module ApplicationHelper
      when 0
        @student_size  ||= searchStudent(course).size
        @homework_size = bid.homeworks.size
-       percent = @homework_size.to_f / @student_size
+       percent = @homework_size.to_f / (@student_size == 0 ? 1 : @student_size)
        confirm_info = "目前#{@student_size}个学生,总共提交了#{@homework_size}份作业,占#{number_to_percentage(percent * 100, precision: 1)}\n"
      when 1
        @homework_evaluations = 0
@@ -1948,7 +1948,7 @@ module ApplicationHelper
        @has_evaluations = 0
        bid.homeworks.map { |homework| @has_evaluations += homework.rates(:quality).where("seems_rateable_rates.rater_id not in #{teachers}").count}
 
-       percent = @has_evaluations.to_f / @homework_evaluations
+       percent = @has_evaluations.to_f / (@homework_evaluations == 0 ? 1 : @homework_evaluations)
        confirm_info = "目前总共分配了#{@homework_evaluations}份匿评作业,已评价#{@has_evaluations}份作业,占#{number_to_percentage(percent * 100, precision: 1)}\n"
      end
      confirm_info