Hi there @yiqiyt and welcome to the NVIDIA developer forums!
I hope you will understand that we don’t share the exact models that are used for DLSS. But if you check out for example NVIDIA DLSS Overview & Game Integrations | NVIDIA On-Demand during the first 2 to 8 minutes, Andrew describes in some detail how the Deep Learning trainig works. It basically is a combination of traditional convolutional networks with back-propagation and an autoencoder.
If you are looking for details on the “hot off the press” Ray Reconstruction as part of DLSS, I recommend this video: