diff --git a/plugins/modbus/modbus_point.c b/plugins/modbus/modbus_point.c
index 715ef93c..5152b9b9 100644
--- a/plugins/modbus/modbus_point.c
+++ b/plugins/modbus/modbus_point.c
@@ -47,7 +47,7 @@ int modbus_tag_to_point(neu_datatag_t *tag, modbus_point_t *point)
     char area = 0;
     int  n    = sscanf(tag->address, "%hhu!%c%hu", &point->slave_id, &area,
                    &point->start_address);
-    if (n != 3) {
+    if (n != 3 || point->start_address == 0) {
         return NEU_ERR_TAG_ADDRESS_FORMAT_INVALID;
     }
 
diff --git a/plugins/modbus/modbus_req.c b/plugins/modbus/modbus_req.c
index 6367e5ce..35df4faf 100644
--- a/plugins/modbus/modbus_req.c
+++ b/plugins/modbus/modbus_req.c
@@ -43,7 +43,7 @@ void modbus_conn_disconnected(void *data, int fd)
     struct neu_plugin *plugin = (struct neu_plugin *) data;
     (void) fd;
 
-    plugin->common.link_state = NEU_NODE_LINK_STATE_CONNECTING;
+    plugin->common.link_state = NEU_NODE_LINK_STATE_DISCONNECTED;
 }
 
 int modbus_send_msg(void *ctx, uint16_t n_byte, uint8_t *bytes)
diff --git a/plugins/modbus/modbus_tcp.c b/plugins/modbus/modbus_tcp.c
index d84d5884..fbf6e01d 100644
--- a/plugins/modbus/modbus_tcp.c
+++ b/plugins/modbus/modbus_tcp.c
@@ -90,14 +90,14 @@ static int driver_init(neu_plugin_t *plugin)
 
 static int driver_uninit(neu_plugin_t *plugin)
 {
-    if (plugin->stack) {
-        modbus_stack_destroy(plugin->stack);
-    }
-
     if (plugin->conn != NULL) {
         neu_conn_destory(plugin->conn);
     }
 
+    if (plugin->stack) {
+        modbus_stack_destroy(plugin->stack);
+    }
+
     neu_event_close(plugin->events);
 
     plog_info(plugin, "node: modbus uninit ok");
diff --git a/src/connection/connection.c b/src/connection/connection.c
index a5bf1119..ce19fb64 100644
--- a/src/connection/connection.c
+++ b/src/connection/connection.c
@@ -228,7 +228,11 @@ ssize_t neu_conn_send(neu_conn_t *conn, uint8_t *buf, ssize_t len)
             break;
         case NEU_CONN_TCP_CLIENT:
         case NEU_CONN_UDP:
-            ret = send(conn->fd, buf, len, MSG_NOSIGNAL | MSG_DONTWAIT);
+            if (conn->block) {
+                ret = send(conn->fd, buf, len, MSG_NOSIGNAL);
+            } else {
+                ret = send(conn->fd, buf, len, MSG_NOSIGNAL | MSG_DONTWAIT);
+            }
             break;
         case NEU_CONN_TTY_CLIENT:
             ret = write(conn->fd, buf, len);
@@ -472,10 +476,14 @@ static void conn_tcp_server_stop(neu_conn_t *conn)
         for (int i = 0; i < conn->param.params.tcp_server.max_link; i++) {
             if (conn->tcp_server.clients[i].fd > 0) {
                 close(conn->tcp_server.clients[i].fd);
+                conn->tcp_server.clients[i].fd = 0;
             }
         }
 
-        close(conn->fd);
+        if (conn->fd > 0) {
+            close(conn->fd);
+            conn->fd = 0;
+        }
 
         conn->tcp_server.is_listen = false;
     }