The comman methods to directly determinate the soil water characteristic curve have the shortcomings of high cost, complicated and time-consuming. So the empirical formula method to predict soil water characteristic curve is more and more accounted. The main movement characteristics of?fluid are the changes of water transport and storage in the process of entering and filling the pore in unsaturated porous media. This problem can be soled by using Richard equation in COMSOL Multiphysics. The distribution of unsaturated soil average effective saturation was simulated and the average effective saturation in the soil and around sensor was forecasted. The simulation is compared with the actual situation and the results have practical significance.