diff --git a/README.md b/README.md
index 06633bb..8056825 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,13 @@
 Backup file or directory to OSS, can be encrypted.
 
 
+Config read order:
+1. from command line, `--config` or `-c`
+1. from `./oss-backupd-config.json`
+1. from `~/.oss-backupd-config.json`
+1. from `/etc/oss-backupd/config.json`
+
+
 <br>
 
 Use direct signed URL or SDK?