By using finite element method of 3D seepage field, the paper simulated the steady seepage field in chamber group of underground powerhouse. The seepage calculation model was established and the drainage holes position was accurately simulated. It analyzed the seepage field characteristics of the underground powerhouse cavers and the seepage control effect of curtain and drainage . In addition, the effect of the drain holes space for the dam foundation and stilling bucket on the seepage field were analyzed. The results show that seepage control measures can obtain good seepage control effect because of the natural high water level. The role of drainage and decreasing pressure of drainage holes is obvious. The curtain can effectively reduce uplift pressure and distribution of hydraulic gradient, which is conducive to the stability of surrounding rock. The effect of dam foundation and space of bucket drainage hole on seepage field is not obvious.