Abstract: National flash flood survey and estimation was carried out in 2058 counties from 2013 to 2015. This task investigated the basic information of flash flood threatened areas, the distribution of historical flash flood disasters, the current measures applied to flash flood prevention and the distribution of wading engineering. Furthermore, the task classified the flash flood associated dangerous zones, analyzed the present situation of flash flood control capacity of the important villages along rivers and initially proposed flash flood warning indexes. Taking Pubei County as an example, this paper discusses the support for flash flood disaster prevention with results of flash flood survey and estimation. The preliminary analysis shows that the results of flash flood survey and estimation help identify the main flash flood control areas, recognize key flash flood risks faced by these areas, improve the non-engineering measures for flash flood disaster prevention and provide the initial indexes for flash flood warning. Although the results of flash flood investigation and estimation can effectively support flash flood disaster prevention, there are still some problems remaining to be studied, such as the flash flood index determination methods, the reliability of flash flood early warning indexes and so on. The flood flash warning systems under construction in China at present are still static systems, while international advanced early flash flood warning systems are all dynamically calculated and continue to improve. Therefore, the construction of flash flood warning systems still needs more researches and investment.