Abstract: San Gabán Ⅲ Hydropower Station faces technical challenges such as anti-seepage of deep overburden foundations at headworks, resistance to uplift pressure in the reservoir basin, and complex flood discharge conditions.Additionally, the water diversion system involves a long tunnel route, deep burial depth, and high internal water pressure.To address these challenges, the following key technologies were adopted.The flood energy dissipation at the headworks utilizes a composite energy dissipation system, while the regulating reservoir employs a special structure combining double-layer geomembranes with check valves to control uplift.For the headrace system, drilling and blasting excavation and TBM tunneling was implemented, and a air-cushioned surge chamber was installed at the tunnel s end to reduce the length of construction roads and the number of access tunnels.In addition, a scheme that is relatively rare in the design of high-voltage long power generation tunnels at home and abroad, which retains the part of grade Ⅲ and Ⅳ surrounding rock as unlined, was adopted to reduce the workload of concrete lining.The results demonstrate that the engineering design can effectively resolve the aforementioned technical challenges and achieve favorable outcomes.The research findings can serve as a reference for similar high-head, long diversion-type hydropower projects with complex geological conditions.