diff --git a/configs/tood/_base_/tood_reader.yml b/configs/tood/_base_/tood_reader.yml
index 4bfe3b4f9fc1f42be0a65fa90ee97ebd67f9c6c3..2807a2b81b3e19f73791b90d024dcc03c79d3942 100644
--- a/configs/tood/_base_/tood_reader.yml
+++ b/configs/tood/_base_/tood_reader.yml
@@ -1,17 +1,18 @@
 worker_num: 4
 TrainReader:
   sample_transforms:
-  - Decode: {}
-  - RandomFlip: {prob: 0.5}
-  - Resize: {target_size: [800, 1333], keep_ratio: true}
-  - NormalizeImage: {is_scale: true, mean: [0.485, 0.456, 0.406], std: [0.229, 0.224, 0.225]}
-  - Permute: {}
+    - Decode: {}
+    - RandomFlip: {prob: 0.5}
+    - Resize: {target_size: [800, 1333], keep_ratio: true}
+    - NormalizeImage: {is_scale: true, mean: [0.485, 0.456, 0.406], std: [0.229, 0.224, 0.225]}
+    - Permute: {}
   batch_transforms:
-  - PadBatch: {pad_to_stride: 32}
+    - PadBatch: {pad_to_stride: 32}
+    - PadGT: {}
   batch_size: 4
   shuffle: true
   drop_last: true
-  collate_batch: false
+  collate_batch: true
   use_shared_memory: true
 
 
diff --git a/ppdet/data/transform/batch_operators.py b/ppdet/data/transform/batch_operators.py
index c731a5fb3457196f78f17ca64ac730baf7ebf366..1a25237b424182bbf6ffbb8564d78cc2a142d9d6 100644
--- a/ppdet/data/transform/batch_operators.py
+++ b/ppdet/data/transform/batch_operators.py
@@ -47,6 +47,7 @@ __all__ = [
     'PadMaskBatch',
     'Gt2GFLTarget',
     'Gt2CenterNetTarget',
+    'PadGT',
 ]
 
 
@@ -72,13 +73,15 @@ class PadBatch(BaseOperator):
         coarsest_stride = self.pad_to_stride
 
         # multi scale input is nested list
-        if isinstance(samples, typing.Sequence) and len(samples) > 0 and isinstance(samples[0], typing.Sequence):
+        if isinstance(samples,
+                      typing.Sequence) and len(samples) > 0 and isinstance(
+                          samples[0], typing.Sequence):
             inner_samples = samples[0]
         else:
             inner_samples = samples
 
-        max_shape = np.array([data['image'].shape for data in inner_samples]).max(
-            axis=0)
+        max_shape = np.array(
+            [data['image'].shape for data in inner_samples]).max(axis=0)
         if coarsest_stride > 0:
             max_shape[1] = int(
                 np.ceil(max_shape[1] / coarsest_stride) * coarsest_stride)
@@ -1066,3 +1069,56 @@ class Gt2CenterNetTarget(BaseOperator):
         sample['size'] = wh
         sample['offset'] = reg
         return sample
+
+
+@register_op
+class PadGT(BaseOperator):
+    """
+    Pad 0 to `gt_class`, `gt_bbox`, `gt_score`...
+    The num_max_boxes is the largest for batch.
+    Args:
+        return_gt_mask (bool): If true, return `pad_gt_mask`,
+                                1 means bbox, 0 means no bbox.
+    """
+
+    def __init__(self, return_gt_mask=True):
+        super(PadGT, self).__init__()
+        self.return_gt_mask = return_gt_mask
+
+    def __call__(self, samples, context=None):
+        num_max_boxes = max([len(s['gt_bbox']) for s in samples])
+        for sample in samples:
+            if self.return_gt_mask:
+                sample['pad_gt_mask'] = np.zeros(
+                    (num_max_boxes, 1), dtype=np.float32)
+            if num_max_boxes == 0:
+                continue
+
+            num_gt = len(sample['gt_bbox'])
+            pad_gt_class = np.zeros((num_max_boxes, 1), dtype=np.int32)
+            pad_gt_bbox = np.zeros((num_max_boxes, 4), dtype=np.float32)
+            if num_gt > 0:
+                pad_gt_class[:num_gt] = sample['gt_class']
+                pad_gt_bbox[:num_gt] = sample['gt_bbox']
+            sample['gt_class'] = pad_gt_class
+            sample['gt_bbox'] = pad_gt_bbox
+            # pad_gt_mask
+            if 'pad_gt_mask' in sample:
+                sample['pad_gt_mask'][:num_gt] = 1
+            # gt_score
+            if 'gt_score' in sample:
+                pad_gt_score = np.zeros((num_max_boxes, 1), dtype=np.float32)
+                if num_gt > 0:
+                    pad_gt_score[:num_gt] = sample['gt_score']
+                sample['gt_score'] = pad_gt_score
+            if 'is_crowd' in sample:
+                pad_is_crowd = np.zeros((num_max_boxes, 1), dtype=np.int32)
+                if num_gt > 0:
+                    pad_is_crowd[:num_gt] = sample['is_crowd']
+                sample['is_crowd'] = pad_is_crowd
+            if 'difficult' in sample:
+                pad_diff = np.zeros((num_max_boxes, 1), dtype=np.int32)
+                if num_gt > 0:
+                    pad_diff[:num_gt] = sample['difficult']
+                sample['difficult'] = pad_diff
+        return samples
diff --git a/ppdet/modeling/assigners/atss_assigner.py b/ppdet/modeling/assigners/atss_assigner.py
index 43e6ae2abbc03d27819145712f7ac91e5469773a..3a9d6f2654677bc4dff63abf24ec60b8bbfd9855 100644
--- a/ppdet/modeling/assigners/atss_assigner.py
+++ b/ppdet/modeling/assigners/atss_assigner.py
@@ -23,10 +23,13 @@ import paddle.nn.functional as F
 
 from ppdet.core.workspace import register
 from ..ops import iou_similarity
+from ..bbox_utils import iou_similarity as batch_iou_similarity
 from ..bbox_utils import bbox_center
-from .utils import (pad_gt, check_points_inside_bboxes, compute_max_iou_anchor,
+from .utils import (check_points_inside_bboxes, compute_max_iou_anchor,
                     compute_max_iou_gt)
 
+__all__ = ['ATSSAssigner']
+
 
 @register
 class ATSSAssigner(nn.Layer):
@@ -77,8 +80,10 @@ class ATSSAssigner(nn.Layer):
                 num_anchors_list,
                 gt_labels,
                 gt_bboxes,
+                pad_gt_mask,
                 bg_index,
-                gt_scores=None):
+                gt_scores=None,
+                pred_bboxes=None):
         r"""This code is based on
             https://github.com/fcjian/TOOD/blob/master/mmdet/core/bbox/assigners/atss_assigner.py
 
@@ -99,18 +104,18 @@ class ATSSAssigner(nn.Layer):
             anchor_bboxes (Tensor, float32): pre-defined anchors, shape(L, 4),
                     "xmin, xmax, ymin, ymax" format
             num_anchors_list (List): num of anchors in each level
-            gt_labels (Tensor|List[Tensor], int64): Label of gt_bboxes, shape(B, n, 1)
-            gt_bboxes (Tensor|List[Tensor], float32): Ground truth bboxes, shape(B, n, 4)
+            gt_labels (Tensor, int64|int32): Label of gt_bboxes, shape(B, n, 1)
+            gt_bboxes (Tensor, float32): Ground truth bboxes, shape(B, n, 4)
+            pad_gt_mask (Tensor, float32): 1 means bbox, 0 means no bbox, shape(B, n, 1)
             bg_index (int): background index
-            gt_scores (Tensor|List[Tensor]|None, float32) Score of gt_bboxes,
+            gt_scores (Tensor|None, float32) Score of gt_bboxes,
                     shape(B, n, 1), if None, then it will initialize with one_hot label
+            pred_bboxes (Tensor, float32, optional): predicted bounding boxes, shape(B, L, 4)
         Returns:
             assigned_labels (Tensor): (B, L)
             assigned_bboxes (Tensor): (B, L, 4)
-            assigned_scores (Tensor): (B, L, C)
+            assigned_scores (Tensor): (B, L, C), if pred_bboxes is not None, then output ious
         """
-        gt_labels, gt_bboxes, pad_gt_scores, pad_gt_mask = pad_gt(
-            gt_labels, gt_bboxes, gt_scores)
         assert gt_labels.ndim == gt_bboxes.ndim and \
                gt_bboxes.ndim == 3
 
@@ -198,9 +203,14 @@ class ATSSAssigner(nn.Layer):
         assigned_bboxes = assigned_bboxes.reshape([batch_size, num_anchors, 4])
 
         assigned_scores = F.one_hot(assigned_labels, self.num_classes)
-        if gt_scores is not None:
+        if pred_bboxes is not None:
+            # assigned iou
+            ious = batch_iou_similarity(gt_bboxes, pred_bboxes) * mask_positive
+            ious = ious.max(axis=-2).unsqueeze(-1)
+            assigned_scores *= ious
+        elif gt_scores is not None:
             gather_scores = paddle.gather(
-                pad_gt_scores.flatten(), assigned_gt_index.flatten(), axis=0)
+                gt_scores.flatten(), assigned_gt_index.flatten(), axis=0)
             gather_scores = gather_scores.reshape([batch_size, num_anchors])
             gather_scores = paddle.where(mask_positive_sum > 0, gather_scores,
                                          paddle.zeros_like(gather_scores))
diff --git a/ppdet/modeling/assigners/task_aligned_assigner.py b/ppdet/modeling/assigners/task_aligned_assigner.py
index 7e31c8afcb360918338aaa377dfc08046af894ab..f45ba4a3b8b6529e6ecc982dfbaeb623ed4ce83d 100644
--- a/ppdet/modeling/assigners/task_aligned_assigner.py
+++ b/ppdet/modeling/assigners/task_aligned_assigner.py
@@ -22,9 +22,11 @@ import paddle.nn.functional as F
 
 from ppdet.core.workspace import register
 from ..bbox_utils import iou_similarity
-from .utils import (pad_gt, gather_topk_anchors, check_points_inside_bboxes,
+from .utils import (gather_topk_anchors, check_points_inside_bboxes,
                     compute_max_iou_anchor)
 
+__all__ = ['TaskAlignedAssigner']
+
 
 @register
 class TaskAlignedAssigner(nn.Layer):
@@ -43,8 +45,10 @@ class TaskAlignedAssigner(nn.Layer):
                 pred_scores,
                 pred_bboxes,
                 anchor_points,
+                num_anchors_list,
                 gt_labels,
                 gt_bboxes,
+                pad_gt_mask,
                 bg_index,
                 gt_scores=None):
         r"""This code is based on
@@ -61,20 +65,18 @@ class TaskAlignedAssigner(nn.Layer):
             pred_scores (Tensor, float32): predicted class probability, shape(B, L, C)
             pred_bboxes (Tensor, float32): predicted bounding boxes, shape(B, L, 4)
             anchor_points (Tensor, float32): pre-defined anchors, shape(L, 2), "cxcy" format
-            gt_labels (Tensor|List[Tensor], int64): Label of gt_bboxes, shape(B, n, 1)
-            gt_bboxes (Tensor|List[Tensor], float32): Ground truth bboxes, shape(B, n, 4)
+            num_anchors_list (List): num of anchors in each level, shape(L)
+            gt_labels (Tensor, int64|int32): Label of gt_bboxes, shape(B, n, 1)
+            gt_bboxes (Tensor, float32): Ground truth bboxes, shape(B, n, 4)
+            pad_gt_mask (Tensor, float32): 1 means bbox, 0 means no bbox, shape(B, n, 1)
             bg_index (int): background index
-            gt_scores (Tensor|List[Tensor]|None, float32) Score of gt_bboxes,
-                    shape(B, n, 1), if None, then it will initialize with one_hot label
+            gt_scores (Tensor|None, float32) Score of gt_bboxes, shape(B, n, 1)
         Returns:
             assigned_labels (Tensor): (B, L)
             assigned_bboxes (Tensor): (B, L, 4)
             assigned_scores (Tensor): (B, L, C)
         """
         assert pred_scores.ndim == pred_bboxes.ndim
-
-        gt_labels, gt_bboxes, pad_gt_scores, pad_gt_mask = pad_gt(
-            gt_labels, gt_bboxes, gt_scores)
         assert gt_labels.ndim == gt_bboxes.ndim and \
                gt_bboxes.ndim == 3
 
diff --git a/ppdet/modeling/heads/tood_head.py b/ppdet/modeling/heads/tood_head.py
index f2cb2970a2d30f33376f3b1ab7bf4f1dab4be5a1..ac8a0f287b545766a780fabbc6e9ac957ad764d7 100644
--- a/ppdet/modeling/heads/tood_head.py
+++ b/ppdet/modeling/heads/tood_head.py
@@ -286,9 +286,11 @@ class TOODHead(nn.Layer):
         return loss
 
     def get_loss(self, head_outs, gt_meta):
-        pred_scores, pred_bboxes, anchors, num_anchors_list, stride_tensor_list = head_outs
+        pred_scores, pred_bboxes, anchors, \
+        num_anchors_list, stride_tensor_list = head_outs
         gt_labels = gt_meta['gt_class']
         gt_bboxes = gt_meta['gt_bbox']
+        pad_gt_mask = gt_meta['pad_gt_mask']
         # label assignment
         if gt_meta['epoch_id'] < self.static_assigner_epoch:
             assigned_labels, assigned_bboxes, assigned_scores = self.static_assigner(
@@ -296,6 +298,7 @@ class TOODHead(nn.Layer):
                 num_anchors_list,
                 gt_labels,
                 gt_bboxes,
+                pad_gt_mask,
                 bg_index=self.num_classes)
             alpha_l = 0.25
         else:
@@ -303,8 +306,10 @@ class TOODHead(nn.Layer):
                 pred_scores.detach(),
                 pred_bboxes.detach() * stride_tensor_list,
                 bbox_center(anchors),
+                num_anchors_list,
                 gt_labels,
                 gt_bboxes,
+                pad_gt_mask,
                 bg_index=self.num_classes)
             alpha_l = -1