降雨作为泥石流的触发因素，常用于泥石流的预警预报，一个地区泥石流发生与否与前期有效累积降雨量和激发雨量相关密切。在对汶川地震灾区已发泥石流灾害的18 个泥石流案例的1 h 激发雨量与流域面积、沟谷长度、松散物质储量、岩石类型、地震动峰值加速度、土地利用类型以及泥石流沟的坡度等影响泥石流活跃性的因子进行主成分分析基础上，选取了6 个主成分对泥石流1 h 雨量激发系数进行拟合，得出了1 h 激发雨量的计算方法。并讨论了该方法在地震灾区的适用性，可为地震灾区泥石流灾害的预警预报提供参考。

There is high relationship between rainfall intensity and trend of debris flow occurrence，so rainfall intensity is usually used for debris flow warning． By using Matlab principle component analysis on driving factors of debris flows are carried out based on 18 debris flows events，which contain watershed area，channel length，volume of loosely material，rock types，soil types，seismic intensity． Finally，6 principle components are selected to generate a multiple liner regression model of the critical rainfall of debris flows． Feasibility of the model is discussed． It can provide reference for warning of debris flow in the stricken area．