diff --git a/mmpose/codecs/spr.py b/mmpose/codecs/spr.py
index 8e09b185c7..fba17f1598 100644
--- a/mmpose/codecs/spr.py
+++ b/mmpose/codecs/spr.py
@@ -138,7 +138,7 @@ def _get_heatmap_weights(self,
         Returns:
             np.ndarray: Heatmap weight array in the same shape with heatmaps
         """
-        heatmap_weights = np.ones(heatmaps.shape) * bg_weight
+        heatmap_weights = np.ones(heatmaps.shape, dtype=np.float32) * bg_weight
         heatmap_weights[heatmaps > 0] = fg_weight
         return heatmap_weights