Abstract: The analysis of flash flood disaster warning index provides an important basis for flash flood disaster forecasting and warning. According to the requirements for flash flood risk warning and real-time dynamic warning, the work contents and key technologies are proposed for corresponding warning periods. On basis of flash flood disaster investigation and evaluation results, the dynamic warning indices with various antecedent rainfall or soil moisture content are determined, considering the influence of soil moisture on runoff yield and confluence processes at small catchment scale, and making full use of various information sources(e.g., forecasting rainfall, real-time monitoring rainfall and water level). The study is expected to provide references for the construction of multi-stage dynamic warning system of flash flood disaster in China.