diff --git a/configs/rotated_rtmdet/_base_/tta.py b/configs/rotated_rtmdet/_base_/tta.py
new file mode 100644
index 000000000..5052d9e17
--- /dev/null
+++ b/configs/rotated_rtmdet/_base_/tta.py
@@ -0,0 +1,35 @@
+tta_model = dict(
+    type='RotatedTTAModel',
+    tta_cfg=dict(nms=dict(type='nms_rotated', iou_threshold=0.1), max_per_img=2000))
+
+img_scales = [(1024, 1024), (800, 800), (1200, 1200)]
+tta_pipeline = [
+    dict(type='mmdet.LoadImageFromFile', file_client_args=dict(backend='disk')),
+    dict(
+        type='mmdet.TestTimeAug',
+        transforms=[
+            [
+                dict(type='mmdet.Resize', scale=s, keep_ratio=True)
+                for s in img_scales
+            ],
+            [
+                # ``RandomFlip`` must be placed before ``Pad``, otherwise
+                # bounding box coordinates after flipping cannot be
+                # recovered correctly.
+                dict(type='mmdet.RandomFlip', prob=1.),
+                dict(type='mmdet.RandomFlip', prob=0.)
+            ],
+            [
+                dict(
+                    type='mmdet.Pad',
+                    size=(1200, 1200),
+                    pad_val=dict(img=(114, 114, 114))),
+            ],
+            [
+                dict(
+                    type='mmdet.PackDetInputs',
+                    meta_keys=('img_id', 'img_path', 'ori_shape', 'img_shape',
+                               'scale_factor', 'flip', 'flip_direction'))
+            ]
+        ])
+]
\ No newline at end of file
diff --git a/configs/rotated_rtmdet/rotated_rtmdet_l-3x-dota.py b/configs/rotated_rtmdet/rotated_rtmdet_l-3x-dota.py
index 7587fbb19..db848bee1 100644
--- a/configs/rotated_rtmdet/rotated_rtmdet_l-3x-dota.py
+++ b/configs/rotated_rtmdet/rotated_rtmdet_l-3x-dota.py
@@ -1,6 +1,6 @@
 _base_ = [
     './_base_/default_runtime.py', './_base_/schedule_3x.py',
-    './_base_/dota_rr.py'
+    './_base_/dota_rr.py', './_base_/tta.py'
 ]
 checkpoint = 'https://download.openmmlab.com/mmdetection/v3.0/rtmdet/cspnext_rsb_pretrain/cspnext-l_8xb256-rsb-a1-600e_in1k-6a760974.pth'  # noqa
 
diff --git a/mmrotate/models/__init__.py b/mmrotate/models/__init__.py
index ca7701153..8de05b912 100644
--- a/mmrotate/models/__init__.py
+++ b/mmrotate/models/__init__.py
@@ -7,4 +7,5 @@
 from .necks import *  # noqa: F401, F403
 from .roi_heads import *  # noqa: F401, F403
 from .task_modules import *  # noqa: F401,F403
+from .test_time_augs import *  # noqa: F401, F403
 from .utils import *  # noqa: F401, F403
diff --git a/mmrotate/models/test_time_augs/__init__.py b/mmrotate/models/test_time_augs/__init__.py
new file mode 100644
index 000000000..329cb3499
--- /dev/null
+++ b/mmrotate/models/test_time_augs/__init__.py
@@ -0,0 +1,7 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+from .rotated_tta import RotatedTTAModel
+
+
+__all__ = [
+  'RotatedTTAModel'
+]
\ No newline at end of file
diff --git a/mmrotate/models/test_time_augs/rotated_tta.py b/mmrotate/models/test_time_augs/rotated_tta.py
new file mode 100644
index 000000000..d019d32d0
--- /dev/null
+++ b/mmrotate/models/test_time_augs/rotated_tta.py
@@ -0,0 +1,71 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+from typing import List, Tuple
+
+import torch
+
+from torch import Tensor
+
+from mmdet.models.test_time_augs import DetTTAModel
+from mmrotate.registry import MODELS
+
+
+def bbox_flip(bboxes: Tensor,
+              img_shape: Tuple[int],
+              direction: str = 'horizontal') -> Tensor:
+    """Flip bboxes horizontally or vertically.
+
+    Args:
+        bboxes (Tensor): Shape (..., 5*k)
+        img_shape (Tuple[int]): Image shape.
+        direction (str): Flip direction, options are "horizontal", "vertical",
+            "diagonal". Default: "horizontal"
+
+    Returns:
+        Tensor: Flipped bboxes.
+    """
+    assert bboxes.shape[-1] % 5 == 0
+    assert direction in ['horizontal', 'vertical', 'diagonal']
+    flipped = bboxes.clone()
+    if direction == 'horizontal':
+        flipped[..., 0] = img_shape[1] - flipped[..., 0]
+        flipped[..., 4] = -flipped[..., 4]
+    elif direction == 'vertical':
+        flipped[..., 1] = img_shape[0] - flipped[..., 1]
+        flipped[..., 4] = -flipped[..., 4]
+    else:
+        flipped[..., 0] = img_shape[1] - flipped[..., 0]
+        flipped[..., 1] = img_shape[0] - flipped[..., 1]
+    return flipped
+
+@MODELS.register_module()
+class RotatedTTAModel(DetTTAModel):
+
+    def merge_aug_bboxes(self, aug_bboxes: List[Tensor],
+                         aug_scores: List[Tensor],
+                         img_metas: List[str]) -> Tuple[Tensor, Tensor]:
+        """Merge augmented detection bboxes and scores.
+        Args:
+            aug_bboxes (list[Tensor]): shape (n, 5*#class)
+            aug_scores (list[Tensor] or None): shape (n, #class)
+        Returns:
+            tuple[Tensor]: ``bboxes`` with shape (n,5), where
+            4 represent (x, y, w, h, t)
+            and ``scores`` with shape (n,).
+        """
+        recovered_bboxes = []
+        for bboxes, img_info in zip(aug_bboxes, img_metas):
+            ori_shape = img_info['ori_shape']
+            flip = img_info['flip']
+            flip_direction = img_info['flip_direction']
+            if flip:
+                bboxes = bbox_flip(
+                    bboxes=bboxes,
+                    img_shape=ori_shape,
+                    direction=flip_direction)
+            recovered_bboxes.append(bboxes)
+        bboxes = torch.cat(recovered_bboxes, dim=0)
+        if aug_scores is None:
+            return bboxes
+        else:
+            scores = torch.cat(aug_scores, dim=0)
+            return bboxes, scores
\ No newline at end of file
diff --git a/tools/test.py b/tools/test.py
index 4d416112d..9f5498fd7 100644
--- a/tools/test.py
+++ b/tools/test.py
@@ -4,7 +4,7 @@
 import os.path as osp
 
 from mmdet.utils import register_all_modules as register_all_modules_mmdet
-from mmengine.config import Config, DictAction
+from mmengine.config import Config, ConfigDict, DictAction
 from mmengine.evaluator import DumpResults
 from mmengine.registry import RUNNERS
 from mmengine.runner import Runner
@@ -24,6 +24,10 @@ def parse_args():
         '--out',
         type=str,
         help='dump predictions to a pickle file for offline evaluation')
+    parser.add_argument(
+        '--tta',
+        action='store_true',
+        help='Whether to use test time augmentation')
     parser.add_argument(
         '--show', action='store_true', help='show prediction results')
     parser.add_argument(
@@ -103,6 +107,19 @@ def main():
     if args.show or args.show_dir:
         cfg = trigger_visualization_hook(cfg, args)
 
+    if args.tta:
+        assert 'tta_model' in cfg, 'Cannot find ``tta_model`` in config.' \
+                                   " Can't use tta !"
+        assert 'tta_pipeline' in cfg, 'Cannot find ``tta_pipeline`` ' \
+                                      "in config. Can't use tta !"
+
+        cfg.model = ConfigDict(**cfg.tta_model, module=cfg.model)
+        test_data_cfg = cfg.test_dataloader.dataset
+        while 'dataset' in test_data_cfg:
+            test_data_cfg = test_data_cfg['dataset']
+
+        test_data_cfg.pipeline = cfg.tta_pipeline
+
     # build the runner from config
     if 'runner_type' not in cfg:
         # build the default runner