diff --git a/bash/delete_than.sh b/bash/delete_than.sh
index 1f1f4d4..a5781eb 100644
--- a/bash/delete_than.sh
+++ b/bash/delete_than.sh
@@ -2,15 +2,16 @@
 set -e
 # 指定文件夹路径
 folder="/home/pi/mp4"
-
+# 进入文件夹
+cd $folder
 # 获取文件夹的大小
-size=$(du -sh "$folder" | awk '{print int($1/1024/1024)}')
+size=$(du -sh "$folder" | awk '{print int($1/1024)}')
 while [[ $size -gt 20 ]]
 do
   # 获取最早创建的文件
-  oldest_file=$(ls -tr | head -1 | xargs)
+  oldest_file=$(ls $folder -tr | head -1 | xargs)
   rm -f $oldest_file
-  size=$(du -sh "$folder" | awk '{print int($1/1024/1024)}')
+  size=$(du -sh "$folder" | awk '{print int($1/1024)}')
   if [[ $size -le 20 ]]
   then
     exit 0