diff --git a/plugins/modbus/modbus_point.c b/plugins/modbus/modbus_point.c
index a5dd4aa9..817aba0c 100644
--- a/plugins/modbus/modbus_point.c
+++ b/plugins/modbus/modbus_point.c
@@ -168,7 +168,8 @@ int modbus_tag_to_point(const neu_datatag_t *tag, modbus_point_t *point)
             point->area == MODBUS_AREA_INPUT) {
             ret = NEU_ERR_TAG_TYPE_NOT_SUPPORT;
         } else {
-            if (point->option.bytes.length > 128) {
+            if (point->option.bytes.length > 128 ||
+                point->option.bytes.length % 2 == 1) {
                 return NEU_ERR_TAG_ADDRESS_FORMAT_INVALID;
             }
             point->n_register =
diff --git a/plugins/modbus/modbus_req.c b/plugins/modbus/modbus_req.c
index 0393f5ce..d2f3aae7 100644
--- a/plugins/modbus/modbus_req.c
+++ b/plugins/modbus/modbus_req.c
@@ -152,7 +152,10 @@ int modbus_group_timer(neu_plugin_t *plugin, neu_plugin_group_t *group,
         {
             modbus_point_t *p   = calloc(1, sizeof(modbus_point_t));
             int             ret = modbus_tag_to_point(tag, p);
-            assert(ret == 0);
+            if (ret != NEU_ERR_SUCCESS) {
+                plog_error(plugin, "invalid tag: %s, address: %s", tag->name,
+                           tag->address);
+            }
 
             utarray_push_back(gd->tags, &p);
         }