Abstract: Research results of the formation mechanism of drought-flood abrupt alternation and the   waterlog prevention and reduction measures in China and abroad are summarized. It is widely believed that the formation mechanism of drought-flood abrupt alternation is closely related to atmospheric circulation anomaly, magnetic index change in solar magnetic field, and monsoon and subtropical anticyclone. In the aspect of city waterlogging mechanism, research results have been achieved in urban runoff yield and concentration mechanism, mathematical modeling, and urban underlying surface change affecting on the rainfall runoff process, which laid a solid foundation for further research. Nevertheless most researches so far focused on the droughts and floods in single city instead of seasonal changes. The following problems need to be further explored: the regularity of the evolution of drought-flood abrupt alternation, the influence of drought-flood abrupt alternation on urban drainage system standards and disaster prevention and mitigation, the establishment of city waterlogging model of urban runoff yield model coupled with valley hydrological and hydrodynamics process.

Key words: drought-flood abrupt alternation, mechanism, disaster mitigation measures