Abstract: Based on the current research studies and needs in engineering,presented and discussed the following four fundamental problems of unsaturated seepage were: ①numerical modeling theories,②modeling of rainfall infiltration,③ initial water content and ④hydraulic conductivity and its effect on the numerical simulation.The results of several simulations were presented to demonstrate the importance of these issues on the numerical modeling of unsaturated seepage.It was suggested that more attention should be paid to the experimental study in order to achieve more accurate predictions and to meet the needs of the practical problems.