Laser active imaging system has been widely used in many fields,but it mostly aims at static target,and it limits the application for the moving targets.The laser active imaging system for static target was presented,and then the difference between moving target imaging and static target imaging was analyzed.Defocus effects of relative moving and fixed focus optical system were analyzed,and three laser active imaging models of moving target were established.Finally,on basis of static target imaging,the laser active imaging system of moving target based on range gating was established by tracking object in big view of field with thermal infrared imager and measuring distance in real-time with laser range finder.Balloon image with distance of 500 m and moving velocity of 5 m/s was obtained in the experiment,which provides a reference for further tracking rapid moving target and lays a foundation for acquiring and processing 3D laser image of moving target.