Focusing on investigating the brake squeal problem of a disc brake at 3 000 Hz. To this end, the noise of this frequency is reproduced on the bench, the laser Doppler vibration measurement technology is used to obtain the operational deflection shape（ODS） at this frequency. Finite element analysis（FEA） model is established and modified according to the experimental modal. The complex eigenvalue analysis is adopted to retrieve the complex eigenvalues and mode shapes.The correlation analysis is used to confirm that the complex eigenvalue results are valid for the actual noise ODS results.Afterwards, analysis of the components contribution and the components modal contribution of this unstable mode are used to provide corresponding structural optimization plan, and a bench test has been carried out to verify the effectiveness of this method.