Mountain flood disasters seriously restrict the sustainable development of mountainous tourism destination，and it is important implication that that regionalization of mountain flood disasters risk can prevent and control the disasters.This study carried out the risk assessment system of mountain flood disaster through investigation，data collection and analysis in Lushan mountain tourism destination，and divided the risk of mountain flood by Analytic hierarchy process（AHP）method.The results show that the ten indexes of flood season（e.g.Average monthly rainfall in flood period，24-hour maximum rainfall，water buffer area，slope，slope direction，elevation，soil and rock types，fracture structure，vegetation coverage indexes，disaster point density，etc.）and the five risk assessment indexes（e.g.the tourist attractions，mountain roads，mountain top roads，tourist routes，buildings）are taken as risk assessment indicators.A risk assessment system of mountain flood disaster was formed in Lushan mountain tourism destination.The weight of each index was obtained by AHP method.The spatial superposition analysis and calculation of assessment indexes was carried out by ArcGIS software.The level map of mountain flood risk area was obtained.The results of risk division were in accordance to the actual investigation data.The area of middle and high risk areas accounted for about 16.50% and that of low risk areas was about 39.01% in Lushan mountain.The results provide data support for the prevention and control of mountain flood disaster，and also provide the reference for other mountain tourism destinations.