Abstract: Based on global transmissibility functions and principal component analysis, eigenvalues are extracted to construct damage indices, which are then combined with the statistical information of the damage indices to design thresholds, thereby proposing a novel method for effective structural damage identification. This method could eliminate the need for pre-selecting global transmissibility and replaces frequency band selection with principal components’ selection, thereby avoiding the influence of subjective judgment and frequency band choice on damage detection accuracy. The results from numerical simulations and experimental tests demonstrated effectiveness of the proposed method on both single and multiple damage scenarios across diverse structural forms, including continuous beams, spatial steel trusses, and steel signal towers under different loading conditions. Even under high noise levels and lower level of localized damage, while the damage localizations may spread to adjacent regions, the method still provide reasonable and reliable results.