Abstract：The Houzishi landslide lies in the center area of new Fengjie County Town. On the landslide body，there are a great deal of resident houses and almost 20 relocated organizations including Fengjie passenger transport center，colligation square and so on. It is important to ensure the stability of slope. After the storage of the Three Gorges Reservoir，the landslide body will be subjected to bigger groundwater pressure，and especially，under the circumstance of sudden lowering of water level，dynamic water pressure will be induced in the landslide body，which is negative to the stability of the slope. According to the simulation of the seepage field in many cases，when the water level is suddenly lowered from 175 to 145 m，the dynamic water pressure on the landslide body is 13 times as that of normal water level，so the effect of dynamic water pressure must be considered in the stability calculation. At last，the seepage field under the engineering measures of lowering groundwater table is also simulated to provide theoretical basis for the design of treatment.
