[目的] 对四川省甘洛县2019年群发性山洪泥石流灾害成因机理进行分析，为山区山洪泥石流灾害防控减灾提供参考。[方法] 对2019年甘洛县山洪泥石流灾害开展现场调查，并结合相关影像和雨情数据等资料，对山洪泥石流灾害的影响因素以及形成机理进行分析。[结果] 2019年甘洛县山洪泥石流主要是由于短期强降雨所诱发的，加之区内有丰富的固体物源以及有利的地形地貌条件；山洪泥石流灾害是洪水与固体物质相互作用共同致灾的产物；山洪泥石流运动过程中受到地形以及一些工程设施的影响比较明显；同时山洪泥石流会挤压主河道甚至阻断河道，从而导致更大灾害。[结论] 基于甘洛县山洪泥石流灾害的形成机理与致灾特征，应该以加强灾区生态修复与水土保持为本，采取工程防治与生态防治相结合的治灾措施。
[Objective] The formation mechanism of the group flash flood/debris flow disasters in Ganluo County of Sichuan Province in 2019 was analyzed in order to provide a reference for the prevention and mitigation of flash flood/debris flow disasters in mountainous areas.[Methods] Based on the field investigation of the group flash flood/debris flow disasters in Ganluo County in 2019, combined with relevant images and rainfall data, the influencing factors and formation mechanism of flash flood/debris flow disasters were analyzed.[Results] The flash flood/debris flow disasters in Ganluo County were mainly caused by short-term heavy rainfall, in addition, there were abundant solid resources and favorable landform conditions in the area. The flash flood/debris flow disasters were the production of the interaction between flood and solid materials. The flash flood/debris flow movement was affected by terrain and some engineering facilities. Meanwhile, the flash flood/debris flow squeezed the main channel or even blocked the channel, thus leading to more disasters.[Conclusion] Based on the formation mechanism and disaster-causing characteristics of flash flood/debris flow disasters in Ganluo County, the disaster control measures shuld be based on strengthening ecological restoration and soil and water conservation in disaster-stricken areas, and combining engineering prevention and ecological control.