diff --git a/python/paddle/fluid/layers/learning_rate_scheduler.py b/python/paddle/fluid/layers/learning_rate_scheduler.py
index 716cc7824eff0c56cc55a055310fa8b1913ac5e6..fe9b40b817d75bf3b8c4e7c9b166758e0725fdca 100644
--- a/python/paddle/fluid/layers/learning_rate_scheduler.py
+++ b/python/paddle/fluid/layers/learning_rate_scheduler.py
@@ -209,6 +209,14 @@ def polynomial_decay(learning_rate,
 def piecewise_decay(boundaries, values):
     """Applies piecewise decay to the initial learning rate.
 
+    Args:
+        boundaries: A list of steps numbers.
+        values: A list of learning rate values that will be picked during
+            different step boundaries.
+
+    Returns:
+        The decayed learning rate.
+
     >>> boundaries = [10000, 20000]
     >>> values = [1.0, 0.5, 0.1]
     >>>