diff --git a/ossUpgrade.sh b/ossUpgrade.sh
index 7876022..65051e0 100755
--- a/ossUpgrade.sh
+++ b/ossUpgrade.sh
@@ -35,9 +35,11 @@ function compare(){
   cat ${fileName}_upstream_oss.info
   echo "localTem:" $(pwd)/${fileName}_oss.info
   cat ${fileName}_oss.info
+  # 当上游oss文件meta信息跟下游缓存文件meta信息匹配时, 无需更新
   if [ "${upstreamOssInfoMd5}" = "${locOssInfoMd5}" ];then
     return 0
   else 
+    # 当上游oss文件meta信息跟下游缓存文件meta信息不符时，如果上游信息是空，下游非空，则忽略更新，因为有可能是误判
     if [ "${upstreamOssInfoMd5}" = "d41d8cd98f00b204e9800998ecf8427e" ] || [ "${locOssInfoMd5}" != "d41d8cd98f00b204e9800998ecf8427e" ];then
       echo "maybe a mistake, ignore upgrade"
       return 0