diff --git a/mmseg/datasets/pipelines/formatting.py b/mmseg/datasets/pipelines/formatting.py
index bbc04ba74..9c390022a 100644
--- a/mmseg/datasets/pipelines/formatting.py
+++ b/mmseg/datasets/pipelines/formatting.py
@@ -69,7 +69,8 @@ class PackSegInputs(BaseTransform):
         data_sample = SegDataSample()
         if 'gt_seg_map' in results:
             gt_sem_seg_data = dict(
-                data=results['gt_seg_map'][None, ...].astype(np.int64))
+                data=to_tensor(results['gt_seg_map'][None,
+                                                     ...].astype(np.int64)))
             data_sample.gt_sem_seg = PixelData(**gt_sem_seg_data)
 
         img_meta = {}