diff --git a/modelscope/metrics/accuracy_metric.py b/modelscope/metrics/accuracy_metric.py
index 8a9a7cce..5459ae66 100644
--- a/modelscope/metrics/accuracy_metric.py
+++ b/modelscope/metrics/accuracy_metric.py
@@ -42,7 +42,7 @@ class AccuracyMetric(Metric):
             self.preds.extend(eval_results.tolist())
             self.labels.extend(ground_truths.tolist())
         else:
-            raise 'only support list or np.ndarray'
+            raise Exception('only support list or np.ndarray')
 
     def evaluate(self):
         assert len(self.preds) == len(self.labels)
diff --git a/modelscope/metrics/ned_metric.py b/modelscope/metrics/ned_metric.py
index 1ab97aa8..0a2141cb 100644
--- a/modelscope/metrics/ned_metric.py
+++ b/modelscope/metrics/ned_metric.py
@@ -14,9 +14,9 @@ from .builder import METRICS, MetricKeys
 
 @METRICS.register_module(group_key=default_group, module_name=Metrics.NED)
 class NedMetric(Metric):
-    """The metric computation class for classification classes.
+    """The ned metric computation class for classification classes.
 
-    This metric class calculates accuracy for the whole input batches.
+    This metric class calculates the levenshtein distance between sentences for the whole input batches.
     """
 
     def __init__(self, *args, **kwargs):
@@ -44,13 +44,46 @@ class NedMetric(Metric):
             self.preds.extend(eval_results.tolist())
             self.labels.extend(ground_truths.tolist())
         else:
-            raise 'only support list or np.ndarray'
+            raise Exception('only support list or np.ndarray')
 
     def evaluate(self):
         assert len(self.preds) == len(self.labels)
         return {
             MetricKeys.NED: (np.asarray([
-                self.ned.distance(pred, ref)
+                1.0 - NedMetric._distance(pred, ref)
                 for pred, ref in zip(self.preds, self.labels)
             ])).mean().item()
         }
+
+    @staticmethod
+    def _distance(pred, ref):
+        if pred is None or ref is None:
+            raise TypeError('Argument s0 is NoneType.')
+        if pred == ref:
+            return 0.0
+        if len(pred) == 0:
+            return len(ref)
+        if len(ref) == 0:
+            return len(pred)
+        m_len = max(len(pred), len(ref))
+        if m_len == 0:
+            return 0.0
+
+        def levenshtein(s0, s1):
+            v0 = [0] * (len(s1) + 1)
+            v1 = [0] * (len(s1) + 1)
+
+            for i in range(len(v0)):
+                v0[i] = i
+
+            for i in range(len(s0)):
+                v1[0] = i + 1
+                for j in range(len(s1)):
+                    cost = 1
+                    if s0[i] == s1[j]:
+                        cost = 0
+                    v1[j + 1] = min(v1[j] + 1, v0[j + 1] + 1, v0[j] + cost)
+                v0, v1 = v1, v0
+            return v0[len(s1)]
+
+        return levenshtein(pred, ref) / m_len
diff --git a/tests/trainers/test_ofa_trainer.py b/tests/trainers/test_ofa_trainer.py
index 20acbaac..f627a419 100644
--- a/tests/trainers/test_ofa_trainer.py
+++ b/tests/trainers/test_ofa_trainer.py
@@ -87,7 +87,7 @@ class TestOfaTrainer(unittest.TestCase):
                        'max_image_size': 480,
                        'imagenet_default_mean_and_std': False},
              'pipeline': {'type': 'ofa-ocr-recognition'},
-             'dataset': {'column_map': {'text': 'caption'}},
+             'dataset': {'column_map': {'text': 'label'}},
              'train': {'work_dir': 'work/ckpts/recognition',
                        # 'launcher': 'pytorch',
                        'max_epochs': 1,
@@ -116,7 +116,6 @@ class TestOfaTrainer(unittest.TestCase):
                                      'use_rdrop': True},
                        'hooks': [{'type': 'BestCkptSaverHook',
                                   'metric_key': 'ned',
-                                  'rule': 'min',
                                   'interval': 100},
                                  {'type': 'TextLoggerHook', 'interval': 1},
                                  {'type': 'IterTimerHook'},
@@ -138,11 +137,13 @@ class TestOfaTrainer(unittest.TestCase):
             model=pretrained_model,
             work_dir=WORKSPACE,
             train_dataset=MsDataset.load(
-                'coco_2014_caption',
+                'ocr_fudanvi_zh',
+                subset_name='scene',
                 namespace='modelscope',
                 split='train[:12]'),
             eval_dataset=MsDataset.load(
-                'coco_2014_caption',
+                'ocr_fudanvi_zh',
+                subset_name='scene',
                 namespace='modelscope',
                 split='validation[:4]'),
             cfg_file=config_file)