diff --git a/mmdet3d/evaluation/metrics/waymo_metric.py b/mmdet3d/evaluation/metrics/waymo_metric.py
index 4010efb657..272b8cb0b2 100644
--- a/mmdet3d/evaluation/metrics/waymo_metric.py
+++ b/mmdet3d/evaluation/metrics/waymo_metric.py
@@ -178,7 +178,7 @@ def compute_metrics(self, results: list) -> Dict[str, float]:
         for metric in self.metrics:
             ap_dict = self.waymo_evaluate(
                 pklfile_prefix, metric=metric, logger=logger)
-            metric_dict[metric] = ap_dict
+            metric_dict.update(ap_dict)
         if eval_tmp_dir is not None:
             eval_tmp_dir.cleanup()