diff --git a/docs/source/index.rst b/docs/source/index.rst
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--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -14,6 +14,7 @@ Welcome to diffengine's documentation!
 
    user_guides/config.md
    user_guides/dataset_prepare.md
+   user_guides/aspect_ratio_bucketing.md
 
 
 .. _RunGuides:
diff --git a/docs/source/user_guides/aspect_ratio_bucketing.md b/docs/source/user_guides/aspect_ratio_bucketing.md
new file mode 100644
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@@ -0,0 +1,77 @@
+# Aspect Ratio Bucketing
+
+Training with aspect ratio bucketing can greatly improve the quality of outputs.
+For more details, you can check [NovelAI Aspect Ratio Bucketing](https://github.com/NovelAI/novelai-aspect-ratio-bucketing).
+
+## Finetune
+
+To use Aspect Ratio Bucketing in finetune, you need to follow these steps:
+
+1. Fix the dataset config.
+
+Change `torchvision/Resize` and `RandomCrop` to `MultiAspectRatioResizeCenterCrop`. Also, use `AspectRatioBatchSampler`.
+
+```
+train_pipeline = [
+    dict(type="SaveImageShape"),
+    dict(type='MultiAspectRatioResizeCenterCrop',
+         sizes=[
+             [640, 1536], [768, 1344], [832, 1216], [896, 1152],
+             [1024, 1024], [1152, 896], [1216, 832], [1344, 768], [1536, 640]
+             ],
+         interpolation='bilinear'),
+    dict(type="RandomHorizontalFlip", p=0.5),
+    dict(type="ComputeTimeIds"),
+    dict(type="torchvision/ToTensor"),
+    dict(type="torchvision/Normalize", mean=[0.5], std=[0.5]),
+    dict(type="PackInputs", input_keys=["img", "text", "time_ids"]),
+]
+train_dataloader = dict(
+    ...
+    dataset=dict(
+        ...
+        pipeline=train_pipeline),
+    sampler=dict(type="DefaultSampler", shuffle=True),
+    batch_sampler=dict(type='AspectRatioBatchSampler'),
+)
+```
+
+2. Run training.
+
+## ControlNet
+
+To use Aspect Ratio Bucketing in ControlNet, you need to follow these steps:
+
+1. Fix dataset config.
+
+```
+train_pipeline = [
+    dict(type="SaveImageShape"),
+    dict(
+        type="MultiAspectRatioResizeCenterCrop",
+        sizes=[
+             [640, 1536], [768, 1344], [832, 1216], [896, 1152],
+             [1024, 1024], [1152, 896], [1216, 832], [1344, 768], [1536, 640]
+             ],
+        interpolation='bilinear',
+        keys=["img", "condition_img"]),
+    dict(type="RandomHorizontalFlip", p=0.5, keys=["img", "condition_img"]),
+    dict(type="ComputeTimeIds"),
+    dict(type="torchvision/ToTensor", keys=["img", "condition_img"]),
+    dict(type="DumpImage", max_imgs=10, dump_dir="work_dirs/dump"),
+    dict(type="torchvision/Normalize", mean=[0.5], std=[0.5]),
+    dict(
+        type="PackInputs",
+        input_keys=["img", "condition_img", "text", "time_ids"]),
+]
+train_dataloader = dict(
+    ...
+    dataset=dict(
+        ...
+        pipeline=train_pipeline),
+    sampler=dict(type="DefaultSampler", shuffle=True),
+    batch_sampler=dict(type='AspectRatioBatchSampler'),
+)
+```
+
+2. Run training.