diff --git a/app/controllers/ec_course_evaluations_controller.rb b/app/controllers/ec_course_evaluations_controller.rb
index 52da9c86..58647589 100644
--- a/app/controllers/ec_course_evaluations_controller.rb
+++ b/app/controllers/ec_course_evaluations_controller.rb
@@ -262,8 +262,8 @@ class EcCourseEvaluationsController < ApplicationController
       start_column = 0
     end
 
-    count = @ce.evluation_count * @ce.ec_course_evaluation_subitems.count # 考核次数与分项的笛卡尔积
-    for i in 1 .. @ce.evluation_count do
+    count = (@ce.evluation_count || 1) * (@ce.ec_course_evaluation_subitems.count || 1) # 考核次数与分项的笛卡尔积
+    for i in 1 .. (@ce.evluation_count || 1) do
       @ce.ec_course_evaluation_subitems.each_with_index do |item, j|
         current_column = start_column + @ce.ec_course_evaluation_subitems.count * (i-1) + j
         sheet1[1, current_column] = "#{@ce.name}#{i}#{item.name}"