As one of the serious natural disasters, forest fire has the characteristics of strong suddenness, hard to detect, wide range of disaster, difficult to extinguish and heavy losses. Frequent forest fires put forward an urgent need for dynamic monitoring of forest fire diffusion and prediction of forest fire behavior. This paper constructs a forest fire diffusion model based on cellular automata, and outputs the visualization results of forest fire diffusion by inputting environmental factors such as terrain data, meteorological data and vegetation type data and the location of the fire point. Finally, the model is used to simulate the forest fire diffusion process in Xichang City, Sichuan Province, and the validity of the model is verified by remote sensing images. The results show that the over-fire area obtained by the simulation experiment is similar to the spatial distribution of the over-fire area extracted by Sentinel-2 satellite, which proves that the cellular automata model constructed in this paper has high accuracy.