diff --git a/mindspore/dataset/transforms/c_transforms.py b/mindspore/dataset/transforms/c_transforms.py
index f4b7cde1fa..f3b20e66a6 100644
--- a/mindspore/dataset/transforms/c_transforms.py
+++ b/mindspore/dataset/transforms/c_transforms.py
@@ -32,7 +32,7 @@ class OneHot(cde.OneHotOp):
 
     Args:
         num_classes (int): Number of classes of the label
-            it should be bigger than or equal to label class number.
+            it should be bigger than largest label number in dataset.
 
     Raises:
         RuntimeError: feature size is bigger than num_classes.