Abstract:A matrix decomposition method is presented，which is applied to 3-D reconstruction of Inverse Synthetic Aperture Radar(ISAR) target. By the modeling of target motion in the scene, the ISAR imaging process of the target is given. The projection matrix of the relationship between two-dimensional position coordinates of scattering point in image sequence and the three-dimensional coordinates for original target is derived. By using the basic method of matrix decomposition based on orthogonal projection, the decomposition of 3-D position matrix for primary target scattering points from the observation matrix is realized, and then the 3-D position reconstruction for target is completed. The simulation results validate its effectiveness.