Abstract: In this paper,we study and analyzethe characteristics of debris flow in Dongchuan copper mining area by field survey and discuss the cause of debris flow from landform,geological structure,climate, hydrology,vegetation,and human factors such as a long-time exploiting,engineering activities, unrea sonable engineering activities so as to understand the mechanism of forminig debris flow,raise people's awareness of preventing and harnessing the debris flow,and achieve the purpose of preventing and reducing the disaster of debris flow.