Combined with a big scale underground hydropower house,the paper first analyzed its natural vibration characteristics by use of three-dimensional finite element method and carry out the check of resonance vibration. Based on the measured vibration data,it secondly studied the relationship between units and powerhouse structure. Thirdly, the paper made feedback analysis for the vertical dynamic load on unit pier and studied the vibration response of powerhouse structure. Form the numerical simulation, the response of the powerhouse structure can be known. The results can provide reference for the design of the same type of powerhouse structure.