diff --git a/python/paddle/v2/framework/evaluator.py b/python/paddle/v2/framework/evaluator.py
new file mode 100644
index 0000000000000000000000000000000000000000..254dd5f1a33eef17ad7a0117541255a4399ef23c
--- /dev/null
+++ b/python/paddle/v2/framework/evaluator.py
@@ -0,0 +1,59 @@
+import paddle.v2.framework.op as op
+import numpy as np
+import paddle.v2.framework.core as core
+
+
+def avg_accumulate(accumulated_var, per_eval, num_batches, place):
+    t = np.array(accumulated_var.get_tensor())
+    t[0] += per_eval[0]
+    accumulated_var.get_tensor().set([t[0] / float(num_batches)], place)
+
+
+class Evaluator(object):
+    def __init__(self,
+                 scope,
+                 operator='accuracy',
+                 input='Inference',
+                 label='Label',
+                 output='Output',
+                 place=core.CPUPlace()):
+        """
+        create an evaluator for evaluating the inference.
+        NOTE: default run on CPUPlace(), running on GPUPlace doesn't improve performance much.
+
+        :param scope: the scope instance contains the input.
+        :type scope: paddle.v2.framework.core.scope
+        :param operator: operator name for caculating the evaluation for each mini-batch.
+        :type operator: string
+        :param input: output variable name of forward network.
+        :type input: string
+        :param label: variable name of label
+        :type label: string
+        """
+        self.scope = scope
+        self.place = place
+        self.output_name = output
+        self.num_batches = 0
+        # create variable to store accumulated evaluator output
+        eval_name = ''.join([operator, "@Eval"])
+        if scope.find_var(eval_name):
+            raise Exception("evaluator already exist in scope: %s" % eval_name)
+        self.accumulated_var = scope.var(eval_name)
+        t = self.accumulated_var.get_tensor()
+        t.set_dims((1, ))
+        t.set([0.0], place)
+        # self.accumulated_var = block.create_var(block, name=eval_name, shape=(1,))
+        # self.accumulated_var.get_tensor().set([0.0])
+        # create operator of evaluation
+        var_map = dict()  # var name -> variable
+        var_map[input] = [input]
+        var_map[label] = [label]
+        var_map[output] = [output]
+        self.op = op.Operator(operator, **var_map)
+
+    def evaluate(self, ctx, accumulator=avg_accumulate):
+        self.op.run(self.scope, ctx)
+        per_eval = np.array(self.scope.find_var(self.output_name).get_tensor())
+        self.num_batches += 1
+        accumulator(self.accumulated_var, per_eval, self.num_batches,
+                    self.place)
diff --git a/python/paddle/v2/framework/tests/test_evaluator.py b/python/paddle/v2/framework/tests/test_evaluator.py
new file mode 100644
index 0000000000000000000000000000000000000000..0f5aa5645f1b73427f256559fca869b76d3841cc
--- /dev/null
+++ b/python/paddle/v2/framework/tests/test_evaluator.py
@@ -0,0 +1,63 @@
+from paddle.v2.framework.evaluator import Evaluator
+from paddle.v2.framework.op import Operator
+import paddle.v2.framework.core as core
+import unittest
+import op_test
+import numpy as np
+
+
+class TestEvaluator(unittest.TestCase):
+    def setup(self, scope, inputs, outputs):
+        def __create_var__(var_name, arr):
+            np_arr = np.array(arr)
+            scope.var(var_name)
+            # tensor = var.get_tensor()
+            # tensor.set_dims(np_arr.shape)
+
+        for var_name, arr in inputs.iteritems():
+            __create_var__(var_name, arr)
+
+        for var_name, arr in outputs.iteritems():
+            __create_var__(var_name, arr)
+
+    def test_evaluator(self):
+
+        inputs = {
+            'Inference': np.array([[1, 1, 1, 1, 1, 0, 0, 0, 0, 1]]).T,
+            'Label': np.array([1, 1, 1, 1, 1, 0, 0, 0, 0, 0])
+        }
+        outputs = {'Accuracy': np.array([0.9])}
+        out_name = 'Accuracy'
+
+        places = [core.CPUPlace()]
+        if core.is_compile_gpu():
+            places.append(core.GPUPlace(0))
+
+        for place in places:
+            scope = core.Scope()
+            self.setup(scope, inputs, outputs)
+
+            evaluator = Evaluator(
+                scope,
+                operator='accuracy',
+                input='Inference',
+                label='Label',
+                output=out_name,
+                place=place)
+            op_test.set_input(scope, evaluator.op, inputs, place)
+            ctx = core.DeviceContext.create(place)
+
+            for i in range(10):  # simulate 10 mini-batches
+                evaluator.evaluate(ctx)
+
+            actual = np.array(scope.find_var(out_name).get_tensor())
+            print actual
+
+            self.assertTrue(
+                np.allclose(
+                    actual, outputs[out_name], atol=1e-5),
+                "output name: " + out_name + " has diff.")
+
+
+if __name__ == '__main__':
+    unittest.main()