Flood risk assessment is the first step in the flood risk management. Flood risk regionalization, which can help understand the distribution patterns and internal rules of flood risk clearly, is developed based on the flood risk assessment. Firstly, the authors explain concepts of flood risk concerned in order to clarify and standardize them. Secondly, this paper reviews the methods of flood risk assessment and flood risk regionalization. The primary methods of flood risk assessment are geomorphological method, hydrological and hydrodynamic modeling method, system emulation modeling method, historical flood disaster data based method, palaeoflood and historical data method, remote sensing and geographical information system method, system analysis method based on the mechanism of flood, and etc. After a brief summary of the researches on flood risk assessment and flood risk regionalization, some perspectives on flood risk assessment and flood risk regionalization are put forward, such as the data base of flood risk research, temporal- spatial scale of assessment, theories and methods of regionalization, technical measures.