The invention discloses a hydropower house foundation which comprises a soil layer and multiple cement mixed grating piles, wherein the cement mixed grating piles are fixed into the soil layer and arranged in a grating shape. The longitudinal direction of a grating network composed of the multiple cement mixed grating piles is identical to the run-off direction of river water. High-pressure rotary spray connector piles are arranged at intersections of the longitudinal cement mixed grating piles and the transverse cement mixed grating piles in the grating network. Multiple distribution piles fixed into the soil layer are arranged in the middle of each grating of the grating network. A plastic concrete diaphragm wall composed of an end wall and side walls is arranged outside the grating network, and a certain distance is formed between the plastic concrete diaphragm wall and the grating network. The end wall is arranged at the upstream end of the grating network. The side walls are arranged on the two sides of the grating network respectively. The plastic concrete diaphragm wall is fixed into the soil layer. The hydropower house foundation can avoid the problems of insufficient bearing capacity, overlarge settlement deformation, a seepage failure and foundation vibratory liquefaction of a weak foundation of a hydropower house, and is low in construction investment, convenient and fast to construct and capable of being widely applied to the technical field of hydroelectric generation engineering.