A new three-dimensional video imaging lidar system based on acousto-optic laser scanning is presented, this system solves the problems of low imaging speed, large volume, and large quality which exist in the lidar system based on the traditional scanning method. Using two-dimensional acousto-optic scanning technology, the scanning speed can be improved. At the same time, high precision time detection chip is used to measure the time of laser pulse flight, in order to gain the distance of the target with high precision. So high precision and video-frequency three dimensional images is achieved. The principle of the system, system components, and the experimental results are described in detail. When the image resolution is 63 pixel×63 pixel, the imaging speed is 25 frame/s, and that can satisfy the demand of high imaging speed requirements for some special situation.