Abstract: The seepage issues of underground powerhouses have been extensively studied, but there is little researches on seepage problems of semi-underground powerhouses with exposed tops. Firstly the groundwater simulation program MODFLOW is used Qinshuitan Hybrid Pumped Storage Power Station to construct a three-dimensional numerical model, simulating and validating the groundwater flow fields in the study area of the. Additionally, 12 different seepage control schemes for the semi-underground powerhouse are analyzed. The results show that the constructed model provides a good fit to the dynamic groundwater level and all parameters are within a reasonable range. The layout of the drainage gallery is the key factor influencing the seepage control effects. The "four-sided layout" scheme demonstrates the best seepage control with an interception rate of 98.21%, followed by the "three-sided layout" scheme, while the "one-sided layout" scheme performs the worst. The spacing of drainage holes also affects the seepage control performance. Under both the "four-sided layout" and "three-sided layout" schemes, smaller hole spacing results a better seepage control. In actual engineering, the seepage control scheme should be determined by balancing seepage control requirements and engineering costs. The research results provide valuable references for the seepage control design of semi-underground powerhouses.