diff --git a/python/paddle/framework/framework.py b/python/paddle/framework/framework.py
index 5f59da03854205affd9a382bc1e6efee47586257..8da6a10a48527ae622b6cc0e377ca7181fccf4d9 100644
--- a/python/paddle/framework/framework.py
+++ b/python/paddle/framework/framework.py
@@ -72,7 +72,7 @@ def get_default_dtype():
     Args:
         None.
     Returns:
-        The default dtype.
+        String, this global dtype only supports float16, float32, float64.
 
     Examples:
         .. code-block:: python