A microscopic diffusion-reaction model was developed to simulate in-situ ozonation for the remediation of contaminated soil, i.e., to predict the temporal and spatial distribution of target contaminant in the subsurface.The sequential strategy was employed to obtain the numerical solution of the model using finite difference method. A non-uniform grid of discretization points was employed to increase the accuracy of the numerical solution by means of coordinate transformation. One-dimensional column tests were conducted to verify the model. The column was packed with simulated soils that were spiked with 2-chlorophenol. Ozone gas passed through the column at a flow time intervals. Compared the experimental data with the simulated values, it was found that the mathematical model fitted data well during most time of the experiment.