Abstract: Taking an electric vehicle disc brake as the research object, the simplified brake model was calculated and solved based on the harmonic response theory.The three-dimensional model of the disc brake was established by CATIA.The harmonic response of the model was analyzed by changing the damping ratio of the brake in the Workbench platform. The distribution of the amplitudes of the brake disc and the brake block with different damping ratios for different frequencies was obtained. Using shim as the optimization target, brake noise tests were performed on the brakes of non-shim, conventional shim, and sandwich shim by the Dynamometer-GIANT 8600 inertial test bench.The results show that by changing the damping ratio of the brake, the resonance between the brake disc and the pad can be reduced, thereby reducing the vibration and noise.The sandwich-type shim performs better than the traditional shim in the cold test phase, and the noise was reduced by about 50% compared to the traditional shim.