Abstract: In recent years, the flash flood disaster assessment has being implemented across China. This paper reviews flash flood management in both nationwide and abroad; the basic principles and approaches on flash flood hazard assessment in China was introduced. Taking Liuyang County as a typical example for southern China, this paper presented approaches and achievements on flash flood hazard assessment in county-level, including flash flood prone areas, current flood control capacity, and critical rainfall amount on flash flood watches and warnings for each riverside-village. As the geographical, hydrological and meteorological information for each watershed was provided by the topographic map, basic data and investigation on flash flood prone areas in this national project, it is feasible that Distributed Hydrology Model could be widely used in flash flood assessment to obtain more accurate and effective flood information for riverside-villages in large-scale areas. With the development of science and technology, flash flood hazard prevention will be more specific, accurate, automatic and intelligent in future.