diff --git a/src/connection/connection.c b/src/connection/connection.c
index 6e21e48a..70d36f6e 100644
--- a/src/connection/connection.c
+++ b/src/connection/connection.c
@@ -688,12 +688,14 @@ void neu_conn_stream_consume(neu_conn_t *conn, void *context,
                 memset(recv_buf, 0, sizeof(recv_buf));
                 offset = 0;
                 break;
-            } else {
-                assert(used > 0);
-                offset -= used;
-                memmove(recv_buf, recv_buf + used, offset);
             }
         }
+        if (offset != 0) {
+            offset -= neu_protocol_unpack_buf_used_size(&protocol_buf);
+            memmove(recv_buf,
+                    recv_buf + neu_protocol_unpack_buf_used_size(&protocol_buf),
+                    offset);
+        }
     }
 }
 
@@ -717,11 +719,13 @@ void neu_conn_stream_tcp_server_consume(neu_conn_t *conn, int fd, void *context,
                 memset(recv_buf, 0, sizeof(recv_buf));
                 offset = 0;
                 break;
-            } else {
-                assert(used > 0);
-                offset -= used;
-                memmove(recv_buf, recv_buf + used, offset);
             }
         }
+        if (offset != 0) {
+            offset -= neu_protocol_unpack_buf_used_size(&protocol_buf);
+            memmove(recv_buf,
+                    recv_buf + neu_protocol_unpack_buf_used_size(&protocol_buf),
+                    offset);
+        }
     }
 }
\ No newline at end of file