Simulations of the Liesegang pattern formation are presented that are based on a discrete stochastic model. The diffusion term was modeled by random walk using transition probabilities referring to one and two steps. A semi-stochastic model of the precipitation process was created, using Ostwald's supersaturation theory. The calculated variance of zone positions and formation time is in good accordance with the experimental observations of Muller et al. (C) 2003 Elsevier Science B.V. All rights reserved.