This study used a comprehensive hydraulic model test method to conduct in-depth analysis and optimization of the Qiling sluice renovation expansion project in the Shima river basin，the main stream of the Dongguan canal comprehensive improvement.In response to the insufficient dredging of the upstream terrain of the newly expanded gate in the original design plan，which may lead to insufficient flow capacity and unstable flow state，a dredging plan is proposed to reach 6.744 m，optimizing the flow state and velocity distribution.The upstream water level of the gate is 0.16 m and 0.12 m lower than the design value，respectively，meeting the requirements of flow capacity.Optimization design has been carried out for the protection of the bridge piers of the Dongshen water supply aqueduct.By adopting a streamlined protection structure，the disturbance to the water flow has been reduced and the lateral uniformity of the water flow has been improved.The optimized protection schemes for the 5# and 6# bridge piers have resulted in a more uniform distribution of flow velocity at the bottom of the sea overflow section of the new and old gates，and a more stable flow state.The old gate has been reduced from 1.5 m/s to 1.3 m/s，and the new gate has been reduced from 1.2 m/s to 0.6 m/s.A scheme comparison was conducted on the number and net width of different gate openings for the expansion of the gate section，and a layout scheme of 6 m× 9 holes was ultimately recommended.The recommended scheme had an upstream water level of 16.26 m when encountering a 200 year flood，which was 0.07 m lower than the design calculation value.This study successfully optimized the design scheme，improved the safety and efficiency of the Qiling sluice expansion project，and provided a solid scientific basis for the implementation and management of the Qiling sluice expansion project.