diff --git a/paddle/operators/ctc_edit_distance_op.cc b/paddle/operators/ctc_edit_distance_op.cc
index 7b45ccc72e9345767899ca873f788aa401505841..fae5cfc117959fc2229ba71c5a55dffb854abc03 100644
--- a/paddle/operators/ctc_edit_distance_op.cc
+++ b/paddle/operators/ctc_edit_distance_op.cc
@@ -38,11 +38,11 @@ class CTCEditDistanceOpMaker : public framework::OpProtoAndCheckerMaker {
              "(2-D tensor with shape [M x 1]) The indices for "
              "hypothesis string");
     AddInput("X2",
-             "(2-D tensor with shape [batch_size x 1]) The indices "
+             "(2-D tensor with shape [N x 1]) The indices "
              "for reference string.");
     AddAttr<bool>("normalized",
                   "(bool, default false) Indicated whether "
-                  "normalize. the Output(Out) by the length of reference "
+                  "normalize the Output(Out) by the length of reference "
                   "string (X2).")
         .SetDefault(false);
     AddOutput("Out",
diff --git a/paddle/operators/ctc_edit_distance_op.h b/paddle/operators/ctc_edit_distance_op.h
index d0494b4b1b1a4f65635e27d5325e7f232e6aca53..a52960f1ef762c934d3f5060ae2265c4cc7a88f0 100644
--- a/paddle/operators/ctc_edit_distance_op.h
+++ b/paddle/operators/ctc_edit_distance_op.h
@@ -47,20 +47,19 @@ class CTCEditDistanceKernel : public framework::OpKernel<T> {
       auto dist = dist_t.data<T>();
       auto x1 = x1_t->data<T>();
       auto x2 = x2_t->data<T>();
-      for (int i = 0; i < m + 1; ++i) {
-        dist[i * (n + 1)] = i;  // dist[i][0] = i;
+      for (size_t i = 0; i < m + 1; ++i) {
+        dist[i * (n + 1)] = i;
       }
-      for (int j = 0; j < n + 1; ++j) {
-        dist[j] = j;  // dist[0][j] = j;
+      for (size_t j = 0; j < n + 1; ++j) {
+        dist[j] = j;
       }
-      for (int i = 1; i < m + 1; ++i) {
-        for (int j = 1; j < n + 1; ++j) {
+      for (size_t i = 1; i < m + 1; ++i) {
+        for (size_t j = 1; j < n + 1; ++j) {
           int cost = x1[i - 1] == x2[j - 1] ? 0 : 1;
-          int deletions = dist[(i - 1) * (n + 1) + j] + 1;
-          int insertions = dist[i * (n + 1) + (j - 1)] + 1;
-          int substitutions = dist[(i - 1) * (n + 1) + (j - 1)] + cost;
-          dist[i * (n + 1) + j] =
-              std::min(deletions, std::min(insertions, substitutions));
+          int dels = dist[(i - 1) * (n + 1) + j] + 1;
+          int ins = dist[i * (n + 1) + (j - 1)] + 1;
+          int subs = dist[(i - 1) * (n + 1) + (j - 1)] + cost;
+          dist[i * (n + 1) + j] = std::min(dels, std::min(ins, subs));
         }
       }
       distance = dist[m * (n + 1) + n];
diff --git a/python/paddle/v2/framework/tests/test_ctc_edit_distance.py b/python/paddle/v2/framework/tests/test_ctc_edit_distance.py
index a6d9dfdf067d0135a793206d0fc10bd1f98a49ca..8a6b0b5390e4b379ef35e4c05e5b1283e7cf67fe 100644
--- a/python/paddle/v2/framework/tests/test_ctc_edit_distance.py
+++ b/python/paddle/v2/framework/tests/test_ctc_edit_distance.py
@@ -6,9 +6,9 @@ from op_test import OpTest
 def Levenshtein(hyp, ref):
     """ Compute the Levenshtein distance between two strings.
 
-    :param hyp:
+    :param hyp: hypothesis string in index
     :type hyp: list
-    :param ref:
+    :param ref: reference string in index
     :type ref: list
     """
     m = len(hyp)
@@ -44,7 +44,6 @@ class TestCTCEditDistanceOp(OpTest):
         distance = Levenshtein(hyp=x1, ref=x2)
         if normalized is True:
             distance = distance / len(x2)
-        print "distance = ", distance
         self.attrs = {'normalized': normalized}
         self.inputs = {'X1': x1, 'X2': x2}
         self.outputs = {'Out': distance}
@@ -54,7 +53,4 @@ class TestCTCEditDistanceOp(OpTest):
 
 
 if __name__ == '__main__':
-    #x1 = ['c', 'a', 'f', 'e']
-    #x2 = ['c', 'o', 'f', 'f', 'e', 'e']
-    #print Levenshtein(x1, x2)
     unittest.main()