Abstract: Based on systematic field survey and comprehensive analyses, the types, characteristics, influencing factors and mechanism of the deformation and failure of high slopes, located in two sides in the lock site region of a hydropowerstation in southwestChina, were investigated. The research shows thatthere are three types of the deformation and failure model of rock mass, they are sliding-fracturing, bending- fracturing, and flaking-peeling or fracturing-toppling. Therefore, there is a possibility for rock mass to generate the failures of falling and sliding, bending and toppling, and flaking and peeling or fracturing and toppling. Based on the above results, potential influence on the projectwas evaluated.