Abstract: Unique geological,geomorphic,hydrological and climatic conditions cause various kinds of mountainous hazards,especially very serious mudflow hazards,to occur frequently in the Rawu-Lunang section,Sichuan-Tibet Highway.On the basis of previous research and the authors' field investigations,it is thought that the complex geological structures,strong crust movements and rivers erosions,frequent earthquakes,abundant loose deposits,favorable geomorphology,well-developed modern glaciers and plentiful precipitation are the principal causes of triggering frequent mudflows in the study area.For the purpose of more effective disaster prevention and reduction,the rock engineering system(RES) method is adopted to make a quantitative zonation of mudflows in the study area.By comparing the quantitative mudflow zonation with the preliminary qualitative zonation and distribution of mudflows,it is verified that the quantitative mudflow zonation method is correct and feasible.