The alteration procedure of the underground water level is simulated under drizzle and storm rainfall conditions respectively adopting the coupling fem analysis program of surface flow and subsurface flow . the numerical simulation of the underground water level shows that the drain ditch installed over the slope does not have an notable effect on the underground water level 利用降雨条件下地表水入渗和产流耦合的计算程序，模拟了小降雨强度和大雨强度对地下水位变化的影响，并用数值计算给出了地表排水沟对地下水变化的影响不是很显著的结论。
