Noise in the structural vibration signal affects the identification accuracy of the modal parameter and generates false mode. The direct identification method is with lowaccuracy and limited in application scope, while the frequency domain average method could improve the identification accuracy of the modal parameter and be good at identifying the modes drown in noise. The improved LSCE wavelet threshold filtering method,is with remarkable denoise effect, which can reach or even surpass the effect of three times averaging in identification accuracy, and with fast identification. By comparing three structural modal identification methods, it shows that the improved LSCE wavelet threshold filtering method can save test costs and improve the recognition speed and accuracy. The improved LSCE wavelet threshold filtering method shows obvious applicability and generalization.