diff --git a/docs/faq.md b/docs/faq.md
index 59a7bc1cf9..db96da729b 100644
--- a/docs/faq.md
+++ b/docs/faq.md
@@ -54,5 +54,7 @@ data = dict(
         gt_folder='data/val_set5/Set5_mod12',
         pipeline=test_pipeline,
         scale=scale,
-        filename_tmpl='{}'),
+        filename_tmpl='{}')
+
+empty_cache = True  # empty cache in every iteration.
 ```
diff --git a/mmedit/apis/test.py b/mmedit/apis/test.py
index d6be06ac82..c72fb15d43 100644
--- a/mmedit/apis/test.py
+++ b/mmedit/apis/test.py
@@ -63,7 +63,8 @@ def multi_gpu_test(model,
                    gpu_collect=False,
                    save_image=False,
                    save_path=None,
-                   iteration=None):
+                   iteration=None,
+                   empty_cache=False):
     """Test model with multiple gpus.
 
     This method tests model with multiple gpus and collects the results
@@ -82,6 +83,7 @@ def multi_gpu_test(model,
         save_path (str): The path to save image. Default: None.
         iteration (int): Iteration number. It is used for the save image name.
             Default: None.
+        empty_cache (bool): empty cache in every iteration. Default: False.
 
     Returns:
         list: The prediction results.
@@ -105,7 +107,8 @@ def multi_gpu_test(model,
                 iteration=iteration,
                 **data)
         results.append(result)
-
+        if empty_cache:
+            torch.cuda.empty_cache()
         if rank == 0:
             # get batch size
             for _, v in data.items():
diff --git a/tools/test.py b/tools/test.py
index 9a4e361156..3f55e89a36 100644
--- a/tools/test.py
+++ b/tools/test.py
@@ -88,6 +88,7 @@ def main():
     model = build_model(cfg.model, train_cfg=None, test_cfg=cfg.test_cfg)
 
     args.save_image = args.save_path is not None
+    empty_cache = cfg.get('empty_cache', False)
     if not distributed:
         _ = load_checkpoint(model, args.checkpoint, map_location='cpu')
         model = MMDataParallel(model, device_ids=[0])
@@ -115,7 +116,8 @@ def main():
             args.tmpdir,
             args.gpu_collect,
             save_path=args.save_path,
-            save_image=args.save_image)
+            save_image=args.save_image,
+            empty_cache=empty_cache)
 
     if rank == 0:
         print('')