The invention relates to a crane amplitude-variable wire rope anti-twisting device and method and a crane and belongs to the related technical field of engineering machinery. The device comprises a connecting arm. The two ends of the connecting arm are fixedly connected with two steel tubes correspondingly. The end, not connected with the connecting arm, of each steel tube is fixedly connected with an upper steel plate which is fixedly connected with a lower steel plate through fasteners. Through the design of a brand-new structure, the crane amplitude-variable wire rope anti-twisting device can be directly mounted on the tower crane to isolate an amplitude-variable wire rope in a usage state; and then the wire rope is prevented from twisting, and normal construction cannot be affected.