Color-diffusion is an image coloring project based on diffusion models that utilizes the LAB color space to colorize black and white images. The main advantage of this project lies in its ability to use existing grayscale information (L channel) to predict color information (A and B channels) through model training. This technique is significant in the field of image processing, especially in restoring old photographs and artistic creation. As an open-source project, Color-diffusion was quickly developed by the author to satisfy curiosity and gain experience in training a diffusion model from scratch. The project is currently free and has considerable room for improvement.