Abstract: Seepage erosion often occurs on slopes of loose weathered residual soil during heavy rainfall. The loss of fine particles caused by this process will change the permeability and strength of slopes, and then affect the stability of shallow slopes. In this paper, the shallow landslides of the Fanzhang Formation in the mountainous area of southern Anhui Province are taken as the research object, and the shear strength and permeability coefficient of the soil under different particle gradation are obtained, and the actual rainfall is simulated by Geo-Studio software(2017.6.3-2017.7.20)Groundwater level dynamic response and landslide stability under action. The results show that:(1)Particle loss has obvious influence on the shear strength index of residual soil, and its cohesive force decreases with the decrease of particle content, and the internal friction angle increases. (2)The groundwater level of landslide body with different particle size distribution has the same effect on rainfall; the decrease of landslide particle will lead to the decrease of groundwater level. (3)The overall stability of landslide is obviously affected by particle size distribution, which decreases with the decrease of internal particles, and the displacement of landslide increases sharply with the heavy rainfall.