Synthetic aperture ladar (SAL) breaks through the diffraction restrict of laser, which is able to afford the need of high precision and real time imaging for the remote targets and scenes. The development situation of SAL at home and abroad is analyzed in detail, through two aspects of theoretical status and experimental progress. On this basis, the key technologies such as SAL laser source, emission signal waveform, laser transmission characteristics and target reflection characteristics, imaging algorithm and motion compensation are summarized and analyzed. It lays the foundation for further study and practical application of SAL.