diff --git a/python/paddle/v2/parameters.py b/python/paddle/v2/parameters.py
index 475067ef222b6cc6e2e6a93e35c45b3eb788d444..cc3adf6f4842cb0ee354923428b0c13a4aa33c19 100644
--- a/python/paddle/v2/parameters.py
+++ b/python/paddle/v2/parameters.py
@@ -43,9 +43,26 @@ def create(layers):
 
 class Parameters(object):
     """
-    Parameters is a dictionary contains Paddle's parameter. The key of
-    Parameters is the name of parameter. The value of Parameters is a plain
-    :code:`numpy.ndarry` .
+    `Parameters` manages all the learnable parameters in a neural network.
+    It stores parameters' information in an OrderedDict, key of which is
+    the name of a parameter, and value related to a key is a parameter's
+    configuration, such as initialization mean and std, its size, whether it is
+    a static parameter, and so on.
+
+    :param __param_conf__: this member stores the configurations of learnable
+        parameters in a network in an OrderedDict. The parameters are added by
+        following their creation order in the neural network one by one:
+        parameters of the previous layers in a network are careted first.
+        When a user iterates over this dict, he can visit parameters in the
+        network from button to up.
+    :type __param_conf__: OrderedDict
+    :param __gradient_machines__: all of the parameters in a neural network are
+        appended to a Paddle gradient machine, which is used internally to copy
+        the parameter values between the C++ and Python end.
+    :type __gradient_machines__: list
+    :param __tmp_params__: a dict to store dummy parameters if no
+        __gradient_machines__ is appended to `Parameters`.
+    :type __tmp_params__: dict
 
     Basically usage is