diff --git a/lib/tasks/statistic_subject_info.rake b/lib/tasks/statistic_subject_info.rake
index e4cc3b380..71fb8ed36 100644
--- a/lib/tasks/statistic_subject_info.rake
+++ b/lib/tasks/statistic_subject_info.rake
@@ -46,7 +46,7 @@ namespace :subjects do
     if ENV['subject_id'].present?
       subjects = subjects.where(id:ENV['subject_id'])
     end
-    subjects.find_in_batches(batch_size: 50) do |s|
+    subjects.find_in_batches(batch_size: 20) do |s|
       str = []
       Parallel.each(s, in_processes: 6) do |subject|
         puts("---------------------course_info_statistic: #{subject.id}")
@@ -85,7 +85,7 @@ namespace :subjects do
     end
     column_value = "subject_id, shixun_id, stage, shixun_name, challenge_count, course_count, " +
         "school_count, used_count, passed_count, evaluate_count, passed_ave_time, created_at, updated_at"
-    subjects.find_in_batches(batch_size: 50) do |s|
+    subjects.find_in_batches(batch_size: 20) do |s|
       Parallel.each_with_index(s, in_processes: 4) do |subject, index, str = []|
         puts("---------------------shixun_info_statistic: #{subject.id}")
         Rails.logger.info("---------------------shixun_info_statistic: #{subject.id}")