diff --git a/python/paddle/v2/framework/graph.py b/python/paddle/v2/framework/graph.py
index 6f2a76a9835696430ef9a23630736c5d151d8db2..b9356aaf899829fb000956eb86dfc4b082af0b70 100644
--- a/python/paddle/v2/framework/graph.py
+++ b/python/paddle/v2/framework/graph.py
@@ -1,9 +1,44 @@
 import paddle.v2.framework.core as core
+import paddle.v2.framework.proto.framework_pb2 as framework_pb2
 import collections
 
 __all__ = ['Block', 'Variable', 'Program', 'Operator']
 
 
+def get_all_op_protos():
+    """
+    Get all registered op proto from PaddlePaddle C++ end.
+    :return: A list of registered OpProto.
+    """
+    protostrs = core.get_all_op_protos()
+    ret_values = []
+    for pbstr in protostrs:
+        op_proto = framework_pb2.OpProto.FromString(str(pbstr))
+        ret_values.append(op_proto)
+    return ret_values
+
+
+class OpProtoHolder(object):
+    @classmethod
+    def instance(cls):
+        if not hasattr(cls, '_instance'):
+            cls._instance = cls()
+        return cls._instance
+
+    def __init__(self):
+        assert not hasattr(
+            self.__class__,
+            '_instance'), 'Please use `instance()` to get OpProtoHolder opject!'
+        op_protos = get_all_op_protos()
+        self.op_proto_map = {}
+        for proto in op_protos:
+            sefl.op_proto_map[proto.type] = proto
+
+    def get_op_proto(self, type):
+        assert type in self.op_proto_map, "Operator with type \"%s\" has not been registered." % type
+        return self.op_proto_map[type]
+
+
 class Variable(object):
     def __init__(self, block, name=None, shape=None, dtype=None,
                  lod_level=None):
@@ -36,27 +71,50 @@ class Variable(object):
 
 
 class Operator(object):
-    def __init__(self,
-                 block,
-                 proto,
-                 type=None,
-                 inputs=None,
-                 outputs=None,
+    def __init__(self, block, desc, type, inputs=None, outputs=None,
                  attrs=None):
         self.block = block
-        self.proto = proto
-        if type is not None:
-            # TODO.
-            pass
+        self.desc = desc
+        self.proto = OpProtoHolder.instance().get_op_proto(type)
+        self.desc.set_type(type)
+
         if inputs is not None:
-            # TODO
-            pass
+            for in_proto in self.proto.inputs:
+                in_argus = inputs[in_proto.name]
+                if not isinstance(in_argus, list):
+                    in_argus = [in_argus]
+                if not in_proto.duplicable and len(in_argus) > 1:
+                    raise ValueError(
+                        "Input %s expects only one input, but %d are given." %
+                        (in_proto.name, len(in_argus)))
+                in_argu_names = []
+                for argu in in_argus:
+                    in_argu_names.append(argu.name())
+                self.desc.set_input(in_proto.name, in_argu_names)
+
         if outputs is not None:
-            # TODO
-            pass
+            for out_proto in self.proto.outputs:
+                out_argus = outputs[out_proto.name]
+                if not isinstance(out_argus, list):
+                    out_argus = [out_argus]
+                if not out_proto.duplicable and len(out_argus) > 1:
+                    raise ValueError(
+                        "Output %s expects only one output, but %d are given." %
+                        (out_proto.name, len(out_argus)))
+                out_argu_names = []
+                for argu in out_argus:
+                    out_argu_names.append(argu.name())
+                self.desc.set_output(out_proto.name, out_argu_names)
+
         if attrs is not None:
-            # TODO
-            pass
+            for attr in self.proto.attrs:
+                attr_name = attr.name
+                if not attr_name in attrs:
+                    continue
+                if not isinstance(attrs[attr_name], Block):
+                    self.desc.set_attr(attr_name, attrs[attr_name])
+                else:
+                    self.desc.set_block_attr(attr_name, attrs[attr_name].desc)
 
         # TODO: Getters
 
@@ -80,8 +138,8 @@ class Block(object):
         return Variable(self, *args, **kwargs)
 
     def append_op(self, *args, **kwargs):
-        op_proto = self.proto.append_op()
-        op = Operator(self, op_proto, *args, **kwargs)
+        op_desc = self.proto.append_op()
+        op = Operator(self, op_desc, *args, **kwargs)
         self.ops.append(op)
         return op