diff --git a/common/xudp/xudp.go b/common/xudp/xudp.go
index a162334a..a3df4e8b 100644
--- a/common/xudp/xudp.go
+++ b/common/xudp/xudp.go
@@ -150,7 +150,7 @@ func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 		case 2:
 			if l != 4 {
 				b.Advance(5)
-				addr, port, err := AddrParser.ReadAddressPort(nil, b)
+				addr, port, err := AddrParser.ReadAddressPort(nil, b) // read addr will read all content and clear b
 				if err != nil {
 					b.Release()
 					return nil, err
diff --git a/common/xudp/xudp_test.go b/common/xudp/xudp_test.go
new file mode 100644
index 00000000..dd720a81
--- /dev/null
+++ b/common/xudp/xudp_test.go
@@ -0,0 +1,36 @@
+package xudp
+
+import (
+	"testing"
+
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/buf"
+	"github.com/xtls/xray-core/common/net"
+)
+
+func TestXudpReadWrite(t *testing.T) {
+	addr, _ := net.ParseDestination("tcp:127.0.0.1:1345")
+	mb := make(buf.MultiBuffer, 0, 16)
+	m := buf.MultiBufferContainer {
+		MultiBuffer: mb,
+	}
+	var arr [8]byte
+	writer := NewPacketWriter(&m, addr, arr)
+
+	source := make(buf.MultiBuffer, 0, 16)
+	b := buf.New()
+	b.WriteByte('a')
+	b.UDP = &addr
+	source = append(source, b)
+	writer.WriteMultiBuffer(source)
+
+	reader := NewPacketReader(&m)
+	dest, err := reader.ReadMultiBuffer()
+	common.Must(err)
+	if dest[0].Byte(0) != 'a' {
+		t.Error("failed to parse xudp buffer")
+	}
+	if dest[0].UDP.Port != 1345 {
+		t.Error("failed to parse xudp buffer")
+	}
+}
\ No newline at end of file