Through the investigation and analysis of 104 unstable slopes in Zhashui County, it is found that the stacked unstable slope is the main slope in the area. The original slopes range is 30~45 degrees, which is most favorable to the development of unstable slopes, and the original height interval which is most conducive to the development of unstable slope is 50~100 m. Due to the weakening of human engineering activities, the development of unstable slopes is reduced in high-steep slopes with original slopes greater than 45° and slope heights greater than 100 m. The deformation and failure modes of unstable slopes are mainly divided into three categories:slip-cracking pattern, slip-compression cracking pattern and bending-cracking pattern and slip-cracking pattern is the most common pattern.