A gantry crane comprising a lightning protection device, wherein the lightning protection device comprises a conductive structure comprising a conductive wire, and the gantry crane has a rail, characterized in that, the lightning protection device further comprises: a rotatable rod structure, comprising a rotatable rod, wherein the rotatable rod is fitted inside an insulating sleeve at the top of the gantry crane; an umbrella net structure, comprising a guide sleeve threadedly and rotatably connected with the rotatable rod in a sleeving manner, wherein the guide sleeve is arranged on an outer circumference of the rotatable rod, at least three conductive longitudinal rods are arranged at intervals in the circumferential direction of the guide sleeve, each of the conductive longitudinal rods has a curved radian, and at least two conductive cross-rings are arranged at intervals and around the conductive longitudinal rods; the radii of the conductive cross-rings are different from each other so that the heights of positions of the conductive cross-rings are also different from each other when the umbrella net structure is unfolded; and the conductive structure further comprises a grounding carbon rod, wherein one end of the conductive wire is fixedly connected with a tail end of the rotatable rod, the other end thereof is connected with the grounding carbon rod, and in a lightning protection state, the conductive longitudinal rods extend out of the insulating sleeve, the conductive cross-rings unfold along the circumferential direction of the conductive longitudinal rods into an umbrella shape, and the conductive cross-rings and the conductive longitudinal rods together form an umbrella-shaped structure covering the upper part of the gantry crane, so that the gantry crane is shielded from lightning, wherein lightning is transmitted to the rotatable rod, and then transmitted to the conductive wire by the rotatable rod, and finally transmitted to the ground through the rail by the conductive wire via the grounding carbon rod. a rotatable rod structure, comprising a rotatable rod, wherein the rotatable rod is fitted inside an insulating sleeve at the top of the gantry crane; an umbrella net structure, comprising a guide sleeve threadedly and rotatably connected with the rotatable rod in a sleeving manner, wherein the guide sleeve is arranged on an outer circumference of the rotatable rod, at least three conductive longitudinal rods are arranged at intervals in the circumferential direction of the guide sleeve, each of the conductive longitudinal rods has a curved radian, and at least two conductive cross-rings are arranged at intervals and around the conductive longitudinal rods; the radii of the conductive cross-rings are different from each other so that the heights of positions of the conductive cross-rings are also different from each other when the umbrella net structure is unfolded; and the conductive structure further comprises a grounding carbon rod, wherein one end of the conductive wire is fixedly connected with a tail end of the rotatable rod, the other end thereof is connected with the grounding carbon rod, and in a lightning protection state, the conductive longitudinal rods extend out of the insulating sleeve, the conductive cross-rings unfold along the circumferential direction of the conductive longitudinal rods into an umbrella shape, and the conductive cross-rings and the conductive longitudinal rods together form an umbrella-shaped structure covering the upper part of the gantry crane, so that the gantry crane is shielded from lightning, wherein lightning is transmitted to the rotatable rod, and then transmitted to the conductive wire by the rotatable rod, and finally transmitted to the ground through the rail by the conductive wire via the grounding carbon rod.