Abstract: The planned Xinjizhou water source site is located on Xinjizhou sandbar in the Nanjing section of the lower reaches of Changjiang River.Surrounded by the river,the project site is a flood passage in the lower reaches of the Changjiang River.In order to ensure the safety of flood control and make rational use of beach resources,we comprehensively reviewed the causes of the recent major floods in the lower reaches of the Changjiang River and the flood crossing scheme in Xinjizhou from the perspective of segmented and classified utilization.We used hydraulic formulas to quantify the capacity of floodwater regulation and storage of the water source project,and used a two-dimensional flow model to quantitatively analyze the impact of the use of water sources project on the flood routing of the project section at each flow level,and analyzed the changes of the flood control situation since the impoundment of the Three Gorges Reservoir based on the measured hydrological data.Based on the above research results,we comprehensively determined a flood control standard of 20-years for the Xinjizhou water source site,and formulated a flood control technical scheme considering the situation of river channel management and dam reinforcement in the lower reaches of the Yangtze River.The standards and scheme can provide decision-making reference for relevant design units,construction units and administrative management departments.