diff --git a/src/config_util.rs b/src/config_util.rs
index c3e6954..6c536ad 100644
--- a/src/config_util.rs
+++ b/src/config_util.rs
@@ -206,9 +206,7 @@ fn real_make_oss_key(oss_backupd_config: &OSSBackupdConfig, oss_backupd_config_i
     key.push_str("/");
     key.push_str(&oss_backupd_config.get_host());
     key.push_str("/");
-    key.push_str(&oss_backupd_config_item.get_file_name());
-    key.push_str("_");
-    key.push_str(&get_now_ymdhms());
+    key.push_str(&format!("{}_{}", &oss_backupd_config_item.get_file_name(), &get_now_ymdhms()));
 
     if !suffix.is_empty() {
         key.push_str(&format!(".{}", suffix));