Abstract: Under the influence of Typhoon Doksuri, the Haihe River basin has a large range and long lasting heavy rainfall process, resulting in Yongding River "23·7" catastrophic flood. In this paper, the rainfall analysis and flood investigation and calculation in Yongding River are carried out comprehensively, and the standards of rainfall, discharge, flood volume and recurrence period for different durations of Yongding River are determined through comparison and analysis with the designed rainfalls, historical floods, measured floods and designed floods, and the change of flood law between Lugouqiao and Sanjiadian section is analyzed in combination with the characteristics of this rainstorm flood. According to the existing problems in the design flood work of Yongding River flood control project and the reality of "23·7" catastrophic flood, this paper puts forward the ideas and suggestions of flood project design, and provides reference for the planning and design of flood project.