diff --git a/PaddleNLP/paddlenlp/datasets/dataset.py b/PaddleNLP/paddlenlp/datasets/dataset.py
index a44a84ddbd45f24c8d61a914e12b7d865a8fec6c..787e4ac4e3d8db01920a37a049cfd754cdcba299 100644
--- a/PaddleNLP/paddlenlp/datasets/dataset.py
+++ b/PaddleNLP/paddlenlp/datasets/dataset.py
@@ -90,25 +90,20 @@ class MapDatasetWrapper(Dataset):
     def __init__(self, data):
         self.data = data
         self._transform_pipline = []
-        self.new_data = []
+        self.new_data = self.data
 
-    def transform(self, data, pipline):
+    def _transform(self, data, pipline):
         for fn in reversed(pipline):
             data = fn(data)
         return data
 
     def __getitem__(self, idx):
-        if not self.new_data:
-            return self.transform(
-                self.data[idx], self._transform_pipline
-            ) if self._transform_pipline else self.data[idx]
-        else:
-            return self.transform(
-                self.new_data[idx], self._transform_pipline
-            ) if self._transform_pipline else self.new_data[idx]
+        return self._transform(
+            self.new_data[idx], self._transform_pipline
+        ) if self._transform_pipline else self.new_data[idx]
 
     def __len__(self):
-        return len(self.data) if not self.new_data else len(self.new_data)
+        return len(self.new_data)
 
     def filter(self, fn):
         """
@@ -120,16 +115,11 @@ class MapDatasetWrapper(Dataset):
         Returns:
             MapDatasetWrapper: The filtered dataset
         """
-        if not self.new_data:
-            self.new_data = [
-                self.data[idx] for idx in range(len(self.data))
-                if fn(self.data[idx])
-            ]
-        else:
-            self.new_data = [
-                self.data[idx] for idx in range(len(self.new_data))
-                if fn(self.new_data[idx])
-            ]
+
+        self.new_data = [
+            self.new_data[idx] for idx in range(len(self.new_data))
+            if fn(self.new_data[idx])
+        ]
         return self
 
     def shard(self, num_shards=None, index=None):
@@ -150,23 +140,17 @@ class MapDatasetWrapper(Dataset):
             num_shards = dist.get_world_size()
         if index is None:
             index = dist.get_rank()
-        num_samples = int(math.ceil(len(self.data) * 1.0 / num_shards))
+
+        num_samples = int(math.ceil(len(self.new_data) * 1.0 / num_shards))
         total_size = num_samples * num_shards
         # add extra samples to make it evenly divisible
-        if not self.new_data:
-            self.new_data = [
-                self.data[idx] for idx in range(len(self.data))
-                if idx % num_shards == index
-            ]
-            if len(self.new_data) < num_samples:
-                self.new_data.append(self.data[index + 1 - num_shards])
-        else:
-            self.new_data = [
-                self.data[idx] for idx in range(len(self.new_data))
-                if idx % num_shards == index
-            ]
-            if len(self.new_data) < num_samples:
-                self.new_data.append(self.new_data[index + 1 - num_shards])
+        self.new_data = [
+            self.new_data[idx] for idx in range(len(self.new_data))
+            if idx % num_shards == index
+        ]
+        if len(self.new_data) < num_samples:
+            self.new_data.append(self.new_data[index + 1 - num_shards])
+
         return self
 
     def apply(self, fn, lazy=False):
@@ -187,15 +171,9 @@ class MapDatasetWrapper(Dataset):
         if lazy:
             self._transform_pipline.append(fn)
         else:
-            if not self.new_data:
-                self.new_data = [
-                    fn(self.data[idx]) for idx in range(len(self.data))
-                ]
-            else:
-                self.new_data = [
-                    fn(self.new_data[idx])
-                    for idx in range(len(self.new_data))
-                ]
+            self.new_data = [
+                fn(self.new_data[idx]) for idx in range(len(self.new_data))
+            ]
         return self
 
     def __getattr__(self, name):