Abstract: The seepage issues of underground powerhouses have been extensively studied, but there is few researches on the seepage problems of semi-underground powerhouses with exposed tops. This study firstly uses the groundwater simulation program MODFLOW to construct a three-dimensional numerical model, simulating and validating the groundwater flow fields in the study area of the Qinshuitan Hybrid Pumped Storage Power Station. Additionally, it analyzes 12 different seepage control schemes for the semi-underground powerhouse. 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 to better seepage control. In actual engineering, the seepage control scheme should be determined by balancing seepage control requirements and engineering costs. The research methods and results provide valuable references for the seepage control design of semi-underground powerhouses.