diff --git a/python/paddle/fluid/incubate/fleet/base/role_maker.py b/python/paddle/fluid/incubate/fleet/base/role_maker.py
index 0ee479dab060ac81f6c961051f8ce51ee9fbce95..06b2c2b28d5668ea5d664ee15d9d69d1fc6b0329 100644
--- a/python/paddle/fluid/incubate/fleet/base/role_maker.py
+++ b/python/paddle/fluid/incubate/fleet/base/role_maker.py
@@ -72,6 +72,12 @@ class MPIRoleMaker(RoleMakerBase):
 
 
 class MPISymetricRoleMaker(MPIRoleMaker):
+    """
+    MPISymetricRoleMaker is designed for worker and server assignment
+    under MPI. Typically, a worker and a server node will be appointed
+    on each physical node. This role maker can be only used under MPI.
+    """
+
     def __init__(self):
         super(MPISymetricRoleMaker, self).__init__()
         self.node_type_ = None