In construction of modern hydropower station, the scale of underground powerhouse is increasingly expanding. Because the area is mostly located below the natural water level which is formed by rainfall, so the area faces with the problem of leakage. Aimd at the complex geological condition and seepage control measures,the paper established 3D finite element model in the areas of powerhouse and dam,and took 3D finite element method to calculate the stable seepage field. The permeability coefficients are determined by the back analysis of finite element model based on boring date. Based on the back analysis, the seepage field characteristics of the underground powerhouse cavers are analyzed and the seepage control effects of two kinds of seepage control schemes are compared. The results show that the hub area with high natural water level and the seepage control measures can obtain good seepage control effect. The closed curtain can obtain better seepage control effect compared with opened curtain. The closed curtain would be the priority to control the powerhouse seepage field from the perspective of seepage control effect and project cost effectiveness.