The invention discloses a corrosion-resisting coating for an old steel tube and an operation method of the corrosion-resisting coating, and belongs to the technical field of metallic surface treatment. The coating is prepared from the following raw materials in percentage by weight: 1 to 3 percent of asphalt, 2 to 6 percent of a dispersing agent, 8 to 15 percent of graphene, 2 to 6 percent of a polyphenyl ether resin powder, 3 to 9 percent of styrene-butadiene rubber, 3 to 6 percent of methylbenzene, 1 to 3 percent of a plasticizer, 1 to 3 percent of a coupling agent, 2 to 4 percent of auxiliary materials, 1 to 3 percent of flame retardant and the balance of water. The corrosion-resisting coating for the old steel tube, disclosed by the invention, adopts a clear preparation principle and ascientific method; the surface of the old steel tube is cleaned by abrasive blasting, shot blasting and high-pressure water jetting, and then corrosion-resisting coating materials are combined with the steel tube by adopting a coating mode to form an integrated structure, wherein the asphalt has the advantages of high adhesion, good chemical reagent resistance and the like; in addition, the graphene has higher hardness, higher strength and heat resistance, so that the protective ability of the coating is improved, high-temperature resistance of the steel tube is enhanced, the use safety of the steel tube is greatly improved and use demands of special occasions are met.