The geological environment of the pump gate hub of the Xianglushan water diversion tunnel is complex, and the construction of the foundation pit project is affected by multiple factors.Therefore, the optimization design of the support structure scheme was carried out for this foundation pit project.Using FLAC 3D, simulation calculations were conducted on the settlement of foundation pits, gate station settlement, and pile displacement under different types of support structures.The evaluation found that the internal support scheme was the best.The results showed that the spacing between cast-in-place piles should not be too long, which can easily cause uncontrollable pile displacement,and it is most suitable to control the pile spacing within 2.5m.The research results can provide reference for the support design and process parameter optimization of hydraulic building foundation pit engineering.