Abstract: This paper develops a damage identification method by synchronal updating of measured modal and finite element model based on the classic sensitivity-based model updating method. A wavelet de-noise treatment is proposed to reduce the noise in mode difference between measured modal and analysis modal of the finite element model according to different time-frequency features between structural modal signal and noise. The de-noising modals are used to construct objective function and the optimal question is solved to update finite element model, then the structural damage can be identified through iterative process. The numerical cases show that the proposed method has a good de-nosing performance and can identify structural damage more accurately.