The hillrock collaping is a pricipal type of erosion in the south of China.In Guangdong province it is characterized with great rainfall.intensive storm,rough texture of soil,and weak ability to resist to the scouring and eroding,it is said that that the artificial activity is fierce is the main factor to cause the collapsing of the hillrock,the scouring of runoff,collapsing and slopeslide,water and gravitational erosion are effected each other.The paper divides the hillrock collapsing into fou types and there stages in decelopement.