diff --git a/ppdet/utils/colormap.py b/ppdet/utils/colormap.py
index a9cdbe891c28d3ee58eda1bce4debe789e03086f..67c68dc1c67e7de5e658d424a3bce9040e73f48f 100644
--- a/ppdet/utils/colormap.py
+++ b/ppdet/utils/colormap.py
@@ -55,4 +55,4 @@ def colormap(rgb=False):
     color_list = color_list.reshape((-1, 3)) * 255
     if not rgb:
         color_list = color_list[:, ::-1]
-    return color_list
+    return color_list.astype('int32')