This article which based on the analysis of the Tibet Linzhi Duobu hydropower stations geological conditions, the review of the permeability coefficient, total water inflow estimation of foundation pit and other foundation researches compares and selects water-lowering schemes when the excavation of underground factory buildings starts. Comparing the impervious curtain and water-lowering scheme with full-well dewatering scheme on applicable conditions, advantages and disadvantages, construction program and cost accounting etc. in detail and the final selection is the "drain openly + the well dewatering program. This article also makes a very detailed discussion on construction management, operation mode, safeguard measures and contingency measures and hopes to have references to the follow-up projects.