Abstract: In order to improve the flood control system for Yingde city and enhance the anti-disaster ability all over the city, the Beijiang stem dike flood control planning has been drawn, which will update the flood control standard to the ever-highest level in 50 years. As the urban area of Yingde city and the protection area of Beijiang River stem dike flood control are both located within the inundated range of the 300-year-return flood, it is necessary to coordinate the flood control operation of the Feilaixia hydroproject to make proper regulation and storage of the flood in the Beijiang River to ensure the safety of the Beijiang River stem dike and its downstream area including Guangzhou city as well as the Pearl River Delta region. To well demonstrate the impacts caused by the constrution of the Yingde Beijiang River stem dike flood control works upon the flood control operation of the Feilaixia hydroproject, a comparative method is adopted to analyze the impacts given by the Yingde Beijiang River stem dike flood control works on the flood control operation of the Feilaixia hydroproject through analog computation of a two-dimensional mathematical model for partially-adjusted and optimized Feilaixia reservoir’s dynamic capacity regulation. The analysis results indicate that the maximum inundated capacity within the Yingde flooding area has a sharp decline after the completion of the Yingde Beijiang stem dike flood control works and so does the inundated area of each flood protection zone. Simultaneously, the water level raises and the discharge increases along the main stream of the Beijiang River and the peak time is advanced as well. Finally, some technical measures such as reserving the entrance of blasting and setting the overflow weir opening will be used to try to reduce the impacts of the Yingde Beijiang River stem dike flood control works to the level before the implementation of the project.