The target echo Directing of Arrival (DOA) estimation algorithm based on array signal processing has the characteristics of strong resolution, high estimation accuracy and strong anti-interference ability. These algorithms are also research hotspots in target direction finding. The Multiple Signal Classification (MUSIC) algorithm is one of the DOA estimation algorithms, and the traditional MUSIC algorithm assumes that the target echoes are not correlated with each other, which leads to its application effect being greatly limited. Based on the traditional MUSIC algorithm, the spatial smoothing MUSIC algorithm is used to decoherence the target echo, and the expression for estimating the target DOA and the implementation flow block diagram of the algorithm are derived. The advantages and disadvantages of the algorithm are compared and analyzed based on the numerical simulation results. The MUSIC algorithm has certain advantages in low-DOA, single target multipath problem, multi-target DOA and targets number estimation.