Abstract: The normal mode interference characteristic in shallow water waveguide is a valuable topic in the fields of underwater acoustic.A method for extracting the interference components of normal modes from broadband acoustic propagation data recorded by a single hydrophone without any prior information is present in this paper.First,a Hermitian matrix is formed by the power spectral density.Second,a singular value decomposition(SVD) is performed on the Hermitian matrix to obtain the orthonormal eigenvectors,which are proportional to the interference components of normal modes.The fundamental equations of the new extracting method are derived based on normal mode and waveguide invariant theory.And the validity of the present method is verified by the numerical simulation and experimental results.In addition,the extracted results of normal-mode interference components are intented to be used for passive localization of broardband sources.