The article presents the results of computer simulation of the process of mutual diffusion of two- component medium. We developed and tested an algorithm simulation of diffusion in a two coextensive medium by cellular automaton and algorithm modeling diffusion neravnoobemnoy environment by direct Monte Carlo simulation. The simulation determined the dependence of the diffusion length of the number of particles participating in the process, and plotted the ratio of components of the medium influence the length of the diffusion process, which may be used to estimate the parameters of the real practical diffusion process.