diff --git a/adapter/outbound/shadowsocks.go b/adapter/outbound/shadowsocks.go
index e6c74592..2edc7080 100644
--- a/adapter/outbound/shadowsocks.go
+++ b/adapter/outbound/shadowsocks.go
@@ -304,7 +304,7 @@ func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
 	switch option.UDPOverTCPVersion {
 	case uot.Version, uot.LegacyVersion:
 	case 0:
-		option.UDPOverTCPVersion = uot.Version
+		option.UDPOverTCPVersion = uot.LegacyVersion
 	default:
 		return nil, fmt.Errorf("ss %s unknown udp over tcp protocol version: %d", addr, option.UDPOverTCPVersion)
 	}