diff --git a/paddle/gserver/evaluators/CTCErrorEvaluator.cpp b/paddle/gserver/evaluators/CTCErrorEvaluator.cpp
index cd4ed19c2ca45c310032c834da4cad56fb1cbdff..e397c71c877dce8c34aefac12481373a037510f6 100644
--- a/paddle/gserver/evaluators/CTCErrorEvaluator.cpp
+++ b/paddle/gserver/evaluators/CTCErrorEvaluator.cpp
@@ -207,7 +207,7 @@ public:
       real err = 0;
       err = editDistance(
           output.value->getData() + output.value->getWidth() * outputStarts[i],
-          output.value->getHeight(), output.value->getWidth(),
+          outputStarts[i+1] - outputStarts[i], output.value->getWidth(),
           label.ids->getData() + labelStarts[i],
           labelStarts[i + 1] - labelStarts[i]);
 
@@ -224,6 +224,9 @@ public:
     for (const std::string& name : config_.input_layers()) {
       arguments.push_back(nn.getLayer(name)->getOutput());
     }
+  }
+
+  virtual void updateSamplesNum(const std::vector<Argument>& arguments) {
     numSequences_ += arguments[1].getNumSequences();
   }
 
diff --git a/paddle/gserver/tests/test_Evaluator.cpp b/paddle/gserver/tests/test_Evaluator.cpp
index 8e857781468fed694dbd061d896263bf05303260..3a591a316b8bafccac9c59ff28e57b4e27f8377a 100644
--- a/paddle/gserver/tests/test_Evaluator.cpp
+++ b/paddle/gserver/tests/test_Evaluator.cpp
@@ -87,18 +87,31 @@ void testEvaluator(TestConfig testConf, string testEvaluatorName,
         return;
     }
 
+    ICpuGpuVectorPtr sequenceStartPositions;
+    if (testConf.inputDefs[i].inputType == INPUT_SEQUENCE_DATA ||
+        testConf.inputDefs[i].inputType == INPUT_SEQUENCE_LABEL) {
+      if (!sequenceStartPositions) {
+        generateSequenceStartPositions(batchSize, sequenceStartPositions);
+      }
+      data.sequenceStartPositions = sequenceStartPositions;
+    }
+
     arguments.push_back(data);
   }
 
   Evaluator* testEvaluator = Evaluator::create(testConf.evaluatorConfig);
   double totalScore = 0.0;
+  testEvaluator->start();
   totalScore += testEvaluator->evalImp(arguments);
   testEvaluator->updateSamplesNum(arguments);
+  testEvaluator->finish();
   LOG(INFO) << *testEvaluator;
 
   double totalScore2 = 0.0;
   if (testConf.testAccumulate) {
+    testEvaluator->start();
     totalScore2 += testEvaluator->evalImp(arguments);
+    testEvaluator->finish();
     EXPECT_LE(fabs(totalScore - totalScore2), 1.0e-5);
   }
 }
@@ -202,6 +215,15 @@ TEST(Evaluator, precision_recall) {
                 false);
 }
 
+TEST(Evaluator, ctc_error_evaluator) {
+  TestConfig config;
+  config.evaluatorConfig.set_type("ctc_edit_distance");
+
+  config.inputDefs.push_back({INPUT_SEQUENCE_DATA, "output", 32});
+  config.inputDefs.push_back({INPUT_SEQUENCE_LABEL, "label", 1});
+  testEvaluatorAll(config, "ctc_error_evaluator", 100);
+}
+
 int main(int argc, char** argv) {
   initMain(argc, argv);
   FLAGS_thread_local_rand_use_global_seed = true;