Abstract: A method is proposed to make the estimation of the covariance become Toeplitz matrix using the Toeplitz characteristic of covariance matrix . It can improve the performance of estimation of DOA in the low SNR and shot snapshot , and dose not add complex multiplication. It is used in the MUSIC algorithm and the PRO-ESPRIT algorithm . The numerical simulation results show that the spatial spectrum and the depth between wave crest and trough are increased in the MUSIC algorithm , and the standard deviations of the estimation of DOA are decreased in the MUSIC algorithm and the PRO-ESPRIT algorithm in the low SNR .The method can be used in other DOA estimation algorithm .