diff --git a/lib/tasks/import_issues_from_chandao.rake b/lib/tasks/import_issues_from_chandao.rake
index ae8e308f6..042e9fee6 100644
--- a/lib/tasks/import_issues_from_chandao.rake
+++ b/lib/tasks/import_issues_from_chandao.rake
@@ -58,8 +58,8 @@ namespace :import_from_chandao do
       issue.priority_id = randd_field_hash['优先级'].to_i
       issue.subject = randd_field_hash['任务名称']
       issue.description = randd_field_hash['任务描述']
-      issue.created_on = randd_field_hash['创建日期'].to_time 
-      issue.updated_on = randd_field_hash['最后修改日期'].to_time rescue randd_field_hash['创建日期'].to_time 
+      issue.created_on = randd_field_hash['创建日期'].to_time rescue nil
+      issue.updated_on = randd_field_hash['最后修改日期'].to_time rescue issue.created_on
       issue.time_scale = randd_field_hash['最初预计'].to_i
       issue.start_date = randd_field_hash['预计开始'].to_time rescue nil
       issue.due_date = randd_field_hash['截止日期'].to_time rescue nil