diff --git a/ppstructure/vqa/eval_ser.py b/ppstructure/vqa/eval_ser.py
index e0612219504aecc01aa4ccae3e3a499ff3d0c639..c9de25fb565cb2efe8b1ba9da28ff96db25b95f8 100644
--- a/ppstructure/vqa/eval_ser.py
+++ b/ppstructure/vqa/eval_ser.py
@@ -61,7 +61,7 @@ def eval(args):
     eval_dataloader = paddle.io.DataLoader(
         eval_dataset,
         batch_size=args.per_gpu_eval_batch_size,
-        num_workers=0,
+        num_workers=8,
         use_shared_memory=True,
         collate_fn=None, )
 
diff --git a/ppstructure/vqa/train_ser.py b/ppstructure/vqa/train_ser.py
index d6c297c499501a6ed81fd37e6d12e40a8d5ff492..58eb09918c33ce53e4248d64d486ef9d29c0d504 100644
--- a/ppstructure/vqa/train_ser.py
+++ b/ppstructure/vqa/train_ser.py
@@ -94,14 +94,14 @@ def train(args):
     train_dataloader = paddle.io.DataLoader(
         train_dataset,
         batch_sampler=train_sampler,
-        num_workers=0,
+        num_workers=8,
         use_shared_memory=True,
         collate_fn=None, )
 
     eval_dataloader = paddle.io.DataLoader(
         eval_dataset,
         batch_size=args.per_gpu_eval_batch_size,
-        num_workers=0,
+        num_workers=8,
         use_shared_memory=True,
         collate_fn=None, )
 
diff --git a/ppstructure/vqa/xfun.py b/ppstructure/vqa/xfun.py
index eb9750dd205e3838fb30cbd5fe3ff419955d19f8..f5dbe507e8f6d22087d7913241f7365cbede9bdf 100644
--- a/ppstructure/vqa/xfun.py
+++ b/ppstructure/vqa/xfun.py
@@ -79,14 +79,36 @@ class XFUNDataset(Dataset):
 
         self.entities_labels = {'HEADER': 0, 'QUESTION': 1, 'ANSWER': 2}
         self.return_keys = {
-            'bbox': 'np',
-            'input_ids': 'np',
-            'labels': 'np',
-            'attention_mask': 'np',
-            'image': 'np',
-            'token_type_ids': 'np',
-            'entities': 'dict',
-            'relations': 'dict',
+            'bbox': {
+                'type': 'np',
+                'dtype': 'int64'
+            },
+            'input_ids': {
+                'type': 'np',
+                'dtype': 'int64'
+            },
+            'labels': {
+                'type': 'np',
+                'dtype': 'int64'
+            },
+            'attention_mask': {
+                'type': 'np',
+                'dtype': 'int64'
+            },
+            'image': {
+                'type': 'np',
+                'dtype': 'float32'
+            },
+            'token_type_ids': {
+                'type': 'np',
+                'dtype': 'int64'
+            },
+            'entities': {
+                'type': 'dict'
+            },
+            'relations': {
+                'type': 'dict'
+            }
         }
 
         if load_mode == "all":
@@ -103,7 +125,7 @@ class XFUNDataset(Dataset):
                       return_special_tokens_mask=False):
         # Padding
         needs_to_be_padded = pad_to_max_seq_len and \
-                             max_seq_len and len(encoded_inputs["input_ids"]) < max_seq_len
+            max_seq_len and len(encoded_inputs["input_ids"]) < max_seq_len
 
         if needs_to_be_padded:
             difference = max_seq_len - len(encoded_inputs["input_ids"])
@@ -412,8 +434,8 @@ class XFUNDataset(Dataset):
         return_data = {}
         for k, v in data.items():
             if k in self.return_keys:
-                if self.return_keys[k] == 'np':
-                    v = np.array(v)
+                if self.return_keys[k]['type'] == 'np':
+                    v = np.array(v, dtype=self.return_keys[k]['dtype'])
                 return_data[k] = v
         return return_data