The invention relates to a protection device for the steel wire rope of a crane, for effectively solving the problems of high workload, risk and poor lubrication effect during lubrication for the steel wire rope. The technical scheme for solution is that the protection device comprises a box body, wherein a static rope and a movable rope penetrate through the box body; the movable rope penetratesthrough a rope guide device, a horizontal rod capable of moving forwards and backwards is arranged above the box body, a line wheel is installed at the front end of the horizontal rod, a vertical bevel gear is installed at the left end of the line wheel, a slide block is arranged on the box body, and a sleeve is connected below the rope guide device; and a rotary shaft is arranged on the box body,a horizontal bevel gear is installed on the rotary shaft, a trigger mechanism is installed on the box body, a plurality of second pressure springs are arranged at the lower end of the rotary shaft, an oil extrusion device is installed on the rotary shaft in a sleeving manner, the oil extrusion device comprises a disc and an annular plate which are coaxial, a shifting sheet capable of rotating andshrinking is arranged on the annular plate, an opening is formed in the disc, an extrusion block is arranged at the left side of the opening, and a circular groove matched with a Z-shaped rod is formed in the rotary shaft. The protection device disclosed by the invention has the advantages of effectively avoiding the risk during manual coating, and being capable of being isolated from the steel wire rope in the case that lubrication is not needed.