In order to explore the problem of interior noise caused by road irregularities and improve vehicle noise performance, a finite element model of entire vehicle, including the cavity and CD tire, is established, and the power spectral density of each tire displacement is computed, based on road noise analysis theory and digital road spectrum excitation calculation methods. Using the random response analysis method, the noise response of the entire vehicle is calculated. The noise response is optimized through transfer path analysis and grid point analysis. The results show that the vehicle interior noise can be significantly reduced by the optimization method, and the reliability of this optimization method and the analysis model is verified.