, A large number of collapse accumulation accumulate on the upper part of the high and steep slopes after the earthquake in the strong earthquake area. The accumulations are far away from the residential area. Once they are induced into the debris flow, a new secondary geological disaster will be formed, which will seriously threaten the lives and property of the residents below. Taking the debris flow of the Pingshiban slope in Kaiping Township of Beichuan County as an example, the collapsed accumulation body of Pingshanbangou “5.12 earthquake” under the influence of strong rainfall turned into a slope debris flow Shijuchangzhen in 2010 and 2013. Based on the introduction of outbreak characteristics of flat stone debris flow, this paper analyzes the starting conditions and influencing factors of collapse accumulation body by the unevenness coefficient of particle size, the discriminating index of starting body for accumulation, and the catchment area of the trailing edge, etc.In response to the development characteristics of such disasters, a prevention and control approach for prevention through upstream stabilization and solid source methods is proposed. In order to provide a reference for the study of starter and control of high and steep slope deposits.#$NLKeywords: collapse accumulation; slope debris flow; unevenness coefficient; discriminant index; prevention