Abstract: Slope of a project for the medium soil slope,similar to arc-shaped,divided into four landslide slip surface,with the exception of a slip surface was edge,other edge of the secondary slide surface after the fall of the bandwidth 3～8m range primary slip direction 240,for the Towed landslide.The main reason is the excavation slope instability and the impact of heavy rain,followed by support and drainage measures are not in place.Research shows that before the landslide damage,low coefficient of stability,in an unstable state,the impact of rainfall,slope vulnerable to instability.