Abstract: Aiming to solve the problem of low efficiency and accuracy when simulating large spreading field forest fires using traditional forest fire spread simulation models, we constructed an improved model coupled with Cellular Automata to ensure=accurate timing of forest fire spread.. We evaluated the impact of time steps on the simulation accuracy to determine an optimal time step value that improves the accuracy and efficiency of large field forest fire simulations. A case study simulation of a spreading forest fire that occurred on Daxing'an Mountain in May 2006 showed that the optimal time step of the forest fire spread geography using a cellular automata simulation algorithm was 1/8 faster when cells were combusted completely. Compared with the real fire situation interpreted from TM image indicates that this model has a higher time and spatial consistency with an average Kappa coefficient of 0.6352, and the average accuracy was 87.89%. This algorithm can be used to simulate and predict forest fire spread in practical applications and the algorithm is reversible.