Collapse erosion is the most serious type of erosion in South China. This paper analyzed the space distri- bution and genesis of collapse erosion. The results show that collapse is mainly distributed in the humid subtropical zones on the south of the Heather River, concentrated in the areas of granite parent materials, and vertically distrib- uted in the hilly regions with a height of 100 ~ 150 meters. The characteristics of formation and distribution are in close connection with the following 3 factors: 1 ) hot and rainy climate in humid subtropical zones provided deep weathering crust and strong erosion dynamic for collapse formation; 2 )Collapse erosion is closely related to the physical properties of weathering crust. Weathering crust particles determines their physical properties. Weathering crust particles is one of the most fundamental factor affecting collapse erosion. Granite weathering crust particles led to its special nature of low shear strength, which tends to collapse instability ; 3 ) the deep soil, runoff scouring and strong gravitational energy in hilly regions cause consequence that soil is prone to collapse into collapse hill.