Abstract: A synthetic aperture lidar is a new imaging system in combination of synthetic aperture signal processing and laser techniques.Firstly,the principle of a synthetic aperture lidar was introduced.And then,some good domestic and foreign experiment results of were described.After analysis of these successful experiments,the key techniques,which are needed to be overcome to make synthetic aperture come into practice were reviewed.Finally,the perspective in military,scientific research and inspection of disaster and environment were put forward.