There is a constant risk to the landslide-prone mass of Laoyingwan Slope in recent years, posing a threat to the security of the first-phase irrigation project of Daqiao Reservoir in Xichang City. Based on engineering surveys, we had better idea of the basic features of the mass's geomorphology, deformation, sliding section, sliding bed and sliding belt, analyzed the formation mechanism of landslide, and obtained physical and mechanical parameters of the sliding mass. Adopting simplified Janbu Method, we made stability calculations and analyses of the slide-prone mass under natural working conditions and heavy rain conditions. Our study shows: the landslide-prone mass of Laoyingwan Slope is of a tractive landslide type, formed mainly due to geomorphology, underground water action and heavy rain, which is liable to slide along the sliding surface. We suggest that residents on this sliding mass be relocated, and the work of monitoring and early warning of possible landslides be improved