Abstract: A summary and review of 16 commonly used algorithms for structure modal parameter identification under the ambient excitation is presented in this paper. After the classification of identification algorithms into time domain and frequency domain, the time domain algorithms are divided into the one-stage methods and two-stage methods ulteriorly based on the process of the algorithms. On the basis of the classification, the applicable condition and basic process of the identification algorithms are described, among which the principle and realizing process of several important algorithms are discussed in detail. The modal validation methods in the structure modal parameter identification are presented basically at the end of this paper.