The automatic double-trolley quay crane completes loading and unloading by the cooperation of the frame trolley system and the main trolley system.It is a conundrum to make the frame trolley system loading and unloading total-automatically and the main trolley system loading and unloading semi-automatically and avoid collision between the spreader and containers.The laser returns when it hits the target object,then we can receive the distance and the angle information of the object by calculating.Using the optical position systems SPSS,TDS and SDS,we can position the spreader and the target container successfully and implement the spreader’s functionof automatic loading and unloading.Moreover, because of the function of positioning for the spatial obstacle,the spreader possesses the functionof avoiding collision.