Abstract: In order to analyze the influence of groundwater seepage on the deformation of colluvial deposit landslide, the formation mechanism of Chunfeng Landslide was discussed, and the influence of groundwater seepage on the stability and deformation of colluvial deposit landslide and old landslide was compared on the base of analyzing geological environmental conditions, morphological characteristics and deformation characteristics of the landslide after field investigation, and numerical simulation was carried out. Some conclusions can be gotten. Firstly, topography, formation lithology, atmospheric precipitation and human engineering activities are the main reasons of Chunfeng Landslide formation. Under the common action of the four factors, the slopes became instable and the deformation or sliding happened in the end. Multiple sliding might happen, and the current accumulation form was formed. Secondly, the influence of groundwater seepage produced by rainfall on stability and deformation of colluvial deposit landslide was very significant. As for the Ⅲ landslide body constituted by colluvial deposit where local overhead was more common, it is easier for the rain to penetrate into the slope, and it is very obvious that groundwater seepage affects the landslide stability and deformation. As for the Ⅰ and Ⅱ old lanslide where local overhead was not common, it is not obvious that groundwater seepage affects landslide stability and deformation. Thirdly, the time and intensity of rainfall were negatively correlated with the landslide stability. When the rainfall intensity is small, the precipitation has little influence on the stability of landslide within a certain period of time, but when the rainfall intensity is large, the stability of landslide will decrease rapidly.