HiDiffusion is a pre-trained diffusion model that can enhance resolution and speed by simply adding one line of code. The model uses techniques such as Resolution-Aware U-Net (RAU-Net) and Modified Shifted Window Multi-head Self-Attention (MSW-MSA) to dynamically adjust feature map sizes to address the issue of object duplication and optimize window attention to reduce computational burden. HiDiffusion can extend image generation resolution to 4096×4096 while maintaining 1.5-6 times the inference speed of previous methods.