diff --git a/vnt/src/channel/sender.rs b/vnt/src/channel/sender.rs
index ec91b42..725445e 100644
--- a/vnt/src/channel/sender.rs
+++ b/vnt/src/channel/sender.rs
@@ -170,7 +170,12 @@ impl PacketSenderInner {
     fn try_send(&self, buf: &[u8]) -> io::Result<()> {
         let len = buf.len();
         let mut buf_vec = Vec::with_capacity(buf.len() + 4);
-        buf_vec.extend_from_slice(&[0, 0, (len >> 8) as u8, (len & 0xFF) as u8]);
+        buf_vec.extend_from_slice(&[
+            (len >> 24) as u8,
+            (len >> 16) as u8,
+            (len >> 8) as u8,
+            len as u8,
+        ]);
         buf_vec.extend_from_slice(buf);
         match self.buffer.try_send(buf_vec) {
             Ok(_) => self.notify.notify(self.token, true),
diff --git a/vnt/src/channel/tcp_channel.rs b/vnt/src/channel/tcp_channel.rs
index cb2b9b9..097c71e 100644
--- a/vnt/src/channel/tcp_channel.rs
+++ b/vnt/src/channel/tcp_channel.rs
@@ -358,7 +358,11 @@ where
     if let Some((route_key, stream, buf, begin)) = map.get_mut(token) {
         loop {
             let end = if *begin >= 4 {
-                4 + (((buf[2] as u16) << 8) | buf[3] as u16) as usize
+                let len = ((buf[0] as usize) << 24)
+                    | ((buf[1] as usize) << 16)
+                    | ((buf[2] as usize) << 8)
+                    | buf[3] as usize;
+                4 + len
             } else {
                 4
             };
diff --git a/vnt/src/protocol/mod.rs b/vnt/src/protocol/mod.rs
index a04e37c..6694771 100644
--- a/vnt/src/protocol/mod.rs
+++ b/vnt/src/protocol/mod.rs
@@ -128,11 +128,10 @@ impl<B: AsRef<[u8]>> NetPacket<B> {
                 "length overflow",
             ));
         }
-        // 不能大于udp最大载荷长度
-        if data_len < 12 || data_len > 65535 - 20 - 8 {
+        if data_len < 12 {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidData,
-                "length overflow",
+                "data_len too short",
             ));
         }
         Ok(NetPacket { data_len, buffer })