Abstract: According to problem that the similar debris flow disasters and accidents happened frequently in the process of mining in China, on the basis of investig ation and statistics, accident data collection and analysis, laboratory studies and the exploration of field, combined with specific mine, the paper analyzed formation fact ors and development rules of similar debris flow disasters that happened in the process of mining and put forward the corresponding prevention measures. The results showed that the similar debris flow under coal mine generally experienced three stages: incubation period, the outbreak period and after outbreak period. The superposi tion fracture zone caused by the combination of riting and looseness due to roadway excavation, water source increased owing to aquifer connection. The essential ter rain factor of the occurrence of debris flow- -the superposition fracture zone formed above the roadway, and the mining effect aroused from roadway excavation. Rifting, aquifer, special terrain and roadway excavation were four essential elements of forming debris flow.