Abstract: The torrential rain on July 20,2021 in Zhengzhou caused serious floods and heavy losses. How should Beijing deal with such extreme heavy rainfall that far exceeds the design standard of urban drainage and waterlogging prevention system? This paper summarizes the current situation and existing problems of drainage and waterlogging prevention in Beijing in recent years,and puts forward some suggestions to deal with the flood disasters including rainfall prediction and early warning,emergency response,rescue and disaster relief and post disaster recovery, in response to the extreme weather such as the "2021.7.20" rainstorm in Zhengzhou.