diff --git a/README.md b/README.md
index c612e08..537d5bb 100644
--- a/README.md
+++ b/README.md
@@ -32,32 +32,37 @@
    - [Multi-layer Perceptron & BP](5_nn/mlp_bp.ipynb)
    - [Softmax & cross-entroy](5_nn/softmax_ce.ipynb)
 7. [PyTorch](6_pytorch/)
-   - [short tutorial](6_pytorch/PyTorch_quick_intro.ipynb)
-   - [basic/Tensor-and-Variable](6_pytorch/0_basic/Tensor-and-Variable.ipynb)
-   - [basic/autograd](6_pytorch/0_basic/autograd.ipynb)
-   - [basic/dynamic-graph](6_pytorch/0_basic/dynamic-graph.ipynb)
-   - [nn/linear-regression-gradient-descend](6_pytorch/1_NN/linear-regression-gradient-descend.ipynb)
-   - [nn/logistic-regression](6_pytorch/1_NN/logistic-regression.ipynb)
-   - [nn/nn-sequential-module](6_pytorch/1_NN/nn-sequential-module.ipynb)
-   - [nn/bp](6_pytorch/1_NN/bp.ipynb)
-   - [nn/deep-nn](6_pytorch/1_NN/deep-nn.ipynb)
-   - [nn/param_initialize](6_pytorch/1_NN/param_initialize.ipynb)
-   - [optim/sgd](6_pytorch/1_NN/optimizer/sgd.ipynb)
-   - [optim/adam](6_pytorch/1_NN/optimizer/adam.ipynb)
-   - [cnn/basic_conv](6_pytorch/2_CNN/basic_conv.ipynb)
-   - [cnn/batch-normalization](6_pytorch/2_CNN/batch-normalization.ipynb)
-   - [cnn/regularization](6_pytorch/2_CNN/regularization.ipynb)
-   - [cnn/lr-decay](6_pytorch/2_CNN/lr-decay.ipynb)
-   - [cnn/vgg](6_pytorch/2_CNN/vgg.ipynb)
-   - [cnn/googlenet](6_pytorch/2_CNN/googlenet.ipynb)
-   - [cnn/densenet](6_pytorch/2_CNN/densenet.ipynb)
-   - [cnn/resnet](6_pytorch/2_CNN/resnet.ipynb)
-   - [rnn/pytorch-rnn](6_pytorch/3_RNN/pytorch-rnn.ipynb)
-   - [rnn/rnn-for-image](6_pytorch/3_RNN/rnn-for-image.ipynb)
-   - [rnn/lstm-time-series](6_pytorch/3_RNN/time-series/lstm-time-series.ipynb)
-   - [gan/autoencoder](6_pytorch/4_GNN/autoencoder.ipynb)
-   - [gan/vae](6_pytorch/4_GNN/vae.ipynb)
-   - [gan/gan](6_pytorch/4_GNN/gan.ipynb)
+   - Basic 
+      - [short tutorial](6_pytorch/PyTorch_quick_intro.ipynb)
+      - [basic/Tensor-and-Variable](6_pytorch/0_basic/Tensor-and-Variable.ipynb)
+      - [basic/autograd](6_pytorch/0_basic/autograd.ipynb)
+      - [basic/dynamic-graph](6_pytorch/0_basic/dynamic-graph.ipynb)
+   - NN & Optimization
+      - [nn/linear-regression-gradient-descend](6_pytorch/1_NN/linear-regression-gradient-descend.ipynb)
+      - [nn/logistic-regression](6_pytorch/1_NN/logistic-regression.ipynb)
+      - [nn/nn-sequential-module](6_pytorch/1_NN/nn-sequential-module.ipynb)
+      - [nn/bp](6_pytorch/1_NN/bp.ipynb)
+      - [nn/deep-nn](6_pytorch/1_NN/deep-nn.ipynb)
+      - [nn/param_initialize](6_pytorch/1_NN/param_initialize.ipynb)
+      - [optim/sgd](6_pytorch/1_NN/optimizer/sgd.ipynb)
+      - [optim/adam](6_pytorch/1_NN/optimizer/adam.ipynb)
+   - CNN
+      - [cnn/basic_conv](6_pytorch/2_CNN/basic_conv.ipynb)
+      - [cnn/batch-normalization](6_pytorch/2_CNN/batch-normalization.ipynb)
+      - [cnn/regularization](6_pytorch/2_CNN/regularization.ipynb)
+      - [cnn/lr-decay](6_pytorch/2_CNN/lr-decay.ipynb)
+      - [cnn/vgg](6_pytorch/2_CNN/vgg.ipynb)
+      - [cnn/googlenet](6_pytorch/2_CNN/googlenet.ipynb)
+      - [cnn/densenet](6_pytorch/2_CNN/densenet.ipynb)
+      - [cnn/resnet](6_pytorch/2_CNN/resnet.ipynb)
+   - RNN
+      - [rnn/pytorch-rnn](6_pytorch/3_RNN/pytorch-rnn.ipynb)
+      - [rnn/rnn-for-image](6_pytorch/3_RNN/rnn-for-image.ipynb)
+      - [rnn/lstm-time-series](6_pytorch/3_RNN/time-series/lstm-time-series.ipynb)
+   - GAN
+      - [gan/autoencoder](6_pytorch/4_GAN/autoencoder.ipynb)
+      - [gan/vae](6_pytorch/4_GAN/vae.ipynb)
+      - [gan/gan](6_pytorch/4_GAN/gan.ipynb)