Abstract: To solve the problem that the array aperture decreases in spatial smoothing for traditional direction of arrival（DOA） estimation of coherent signals, a DOA estimation method using multiple signal classification（MUSIC） algorithm based on the Toeplitz reconstruction of covariance matrix is proposed in this paper. A new covariance matrix is constructed according to the covariance matrix of the signals received by hydrophone array and its flip matrix, and the Toeplitz matrix is reconstructed by the elements of the first row and the first column of the new covariance matrix. Then the noise subspace is obtained by eigenvalue decomposition of the Toeplitz matrix and used to calculate the spatial spectrum. Finally, the DOA estimation problem of incoming signal is solved through spectral peak search. The method in this paper expands the array aperture, increases the number of estimable coherent signals, and improves the performance of azimuth estimation and the spatial resolution of the array. The simulation and data processing results of the lake experiment show that the method in this paper can estimate more coherent signals and still has good estimation performance when the signal-to-noise ratio is low, the snapshot is less, and the incident angle interval is small.