Gantry crane is a kind of deformation of bridge crane. In the port, it is mainly used for the loading and unloading of outdoor freight yard, material yard and bulk cargo. Its metal structure is like a portal frame, carrying two legs under the main beam, which can be directly walked on the ground track, and the main beam can have overhanging cantilever beams at both ends. Gantry crane has the characteristics of high site utilization rate, large operation range, wide adaptability and strong versatility, and has been widely used in port freight yards.