Considering the internal dynamic excitation of gears and the unbalanced inertia excitation of ring-plate, the dynamic finite element model of transmission system and structure system of double-ring gear reducer with central inputting shaft was established, and the natural mode and dynamic response of double-ring gear reducer was calculated by the simulation software of ANSYS. Then the vibration displacement was taken as the boundary condition of housing, an acoustic boundary element model was built. By the software of SYSNOISE, the surface acoustic pressure of reducer and the radiation noise of field points were solved by the direct boundary element method. An experimental bench was used to test the vibration acceleration and radiation noise of reducer. Comparative analysis shows that the computational results are in a good agreement with the data of experiment tests.