diff --git a/fastNLP/api/__init__.py b/fastNLP/api/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/fastNLP/api/pipeline.py b/fastNLP/api/pipeline.py
new file mode 100644
index 00000000..b5c4cc7a
--- /dev/null
+++ b/fastNLP/api/pipeline.py
@@ -0,0 +1,23 @@
+from fastNLP.api.processor import Processor
+
+
+
+class Pipeline:
+    def __init__(self):
+        self.pipeline = []
+
+    def add_processor(self, processor):
+        assert isinstance(processor, Processor), "Must be a Processor, not {}.".format(type(processor))
+        processor_name = type(processor)
+        self.pipeline.append(processor)
+
+    def process(self, dataset):
+        assert len(self.pipeline)!=0, "You need to add some processor first."
+
+        for proc_name, proc in self.pipeline:
+            dataset = proc(dataset)
+
+        return dataset
+
+    def __call__(self, *args, **kwargs):
+        return self.process(*args, **kwargs)
\ No newline at end of file
diff --git a/fastNLP/api/processor.py b/fastNLP/api/processor.py
new file mode 100644
index 00000000..793cfe10
--- /dev/null
+++ b/fastNLP/api/processor.py
@@ -0,0 +1,15 @@
+
+
+class Processor:
+    def __init__(self, field_name, new_added_field_name):
+        self.field_name = field_name
+        if new_added_field_name is None:
+            self.new_added_field_name = field_name
+        else:
+            self.new_added_field_name = new_added_field_name
+
+    def process(self):
+        pass
+
+    def __call__(self, *args, **kwargs):
+        return self.process(*args, **kwargs)
\ No newline at end of file
diff --git a/fastNLP/core/batch.py b/fastNLP/core/batch.py
index b55ae3dd..0381d267 100644
--- a/fastNLP/core/batch.py
+++ b/fastNLP/core/batch.py
@@ -51,34 +51,20 @@ class Batch(object):
             raise StopIteration
         else:
             endidx = min(self.curidx + self.batch_size, len(self.idx_list))
-            batch_idxes = self.idx_list[self.curidx: endidx]
-            padding_length = {field_name: max([field_length[idx] for idx in batch_idxes])
-                              for field_name, field_length in self.lengths.items()}
-            batch_x, batch_y = defaultdict(list), defaultdict(list)
-
-            # transform index to tensor and do padding for sequences
-            batch = []
-            for idx in batch_idxes:
-                x, y = self.dataset.to_tensor(idx, padding_length)
-                batch.append((self.lengths[self.sort_key][idx] if self.sort_in_batch else None, x, y))
-
-            if self.sort_in_batch:
-                batch = sorted(batch, key=lambda x: x[0], reverse=True)
-
-            for _, x, y in batch:
-                for name, tensor in x.items():
-                    batch_x[name].append(tensor)
-                for name, tensor in y.items():
-                    batch_y[name].append(tensor)
-
-            # combine instances to form a batch
-            for batch in (batch_x, batch_y):
-                for name, tensor_list in batch.items():
-                    if self.use_cuda:
-                        batch[name] = torch.stack(tensor_list, dim=0).cuda()
-                    else:
-                        batch[name] = torch.stack(tensor_list, dim=0)
+            batch_x, batch_y = {}, {}
+
+            indices = self.idx_list[self.curidx:endidx]
+
+            for field_name, field in self.dataset.get_fields():
+                batch = field.get(indices)
+                if not field.tensorable: #TODO 修改
+                    pass
+                elif field.is_target:
+                    batch_y[field_name] = batch
+                else:
+                    batch_x[field_name] = batch
 
             self.curidx = endidx
+
             return batch_x, batch_y