Bent is widely used above generator floor elevation in ground hydropower house. In order to study the influence of simulation method of bent on the simulation result of vibration characteristics of power house, we built three finite element models in ANSYS to simulate the natural vibration characteristics and dynamic responses of generator unit under vibration loads. The study shows if the focus was on the free vibration characteristics of floors and columns, the bent could be simulated by mass elements or be ignored because the vibration amplitude and dynamic stress of bent are not the most intensive. In conclusion, unless the vibration amplitude and dynamic stress of bent are main research object, the bent could be simplified, which would exert no impact on the dynamic response of powerhouse structure.