Abstract: Aiming at the problem of low estimation performance of classical direction of arrival (DOA) estimation under low signal-to-noise ratio (SNR), this paper proposes a DOA estimation algorithm which combines the fourth-order cumulant of signal with the expectation maximization algorithm. The method introduces an implicit variable to update and iterate, and finds the fourth-order cumulant of the implicit variable. The maximum likelihood function of the estimated direction of arrival is constructed so as to obtain the direction-of-arrival of the signal. The simulation results show that the proposed algorithm can effectively suppress the influence of Gaussian noise on the signal parameter estimation. Meanwhile, the algorithm using iterative updating can improve the estimation accuracy. It has good performance in low signal-to-noise ratio(SNR) estimation, good stability and resolution, which is beneficial to the high-resolution estimation of DOA.