Infrared searching and tracking (IRST) system has an important position in many fields such as situational awareness and environmental safety monitoring.Image motion compensation is one of the key technologies for fast scanning of IRST.A large area array IRST optical system with image motion compensation under the conditions of long integration time and fast circle scanning is designed, and image stabilization method of parallel optical path is adopted in the optical system.The optical system has the technical characteristics of 4 ms integration time, 360 (°)/s circle scanning rate, and 1k area array scale.The principle of parallel optical path image stabilization is introduced, and the calculation and matching of the parameters are proposed.The results of lens design and circle-scanning imaging tests on optical prototype indicate that the optical system has excellent imaging detection capabilities, and the relevant indexes of the optical system have reached domestic leading level.