From such actual conditions as the effects of fluid mechanics in porous media and three-dimensional geology characteristics, the mathematical model and a kind of modified method of second order splitting-up implicit iterative scheme were put forward. For the actual problem of Dongying hollow ( single layer) and Huimin hollow (muhilayer) of Shengli Petroleum Oil Field, this numerical simulation test and the actual conditions are basically coincident, thus the well-known problem has been solved.