Leak-proof device for hydraulic oil cylinder

The utility model discloses a leakproof device for a hydraulic oil cylinder, and relates to the field of hydraulic oil cylinders. A leakproof device for a hydraulic oil cylinder comprises a suction cylinder, a first piston, a second piston, a first piston and a second piston, wherein the suction cylinder is fixedly mounted on the side wall of a hydraulic oil cylinder; the pull rod is connected in the suction cylinder in a sliding manner; the upper end of the pull rod is fixedly connected with a top block connected with the end part of the piston rod; the annular gas storage tank is fixedly installed at the position, close to an oil seal of the cylinder cover, of the upper end of the hydraulic oil cylinder barrel, and the annular gas storage tank is arranged on the outer side of the piston rod in a sleeving mode; according to the hydraulic oil cylinder, dust attached to the piston rod can be blown away, the situation that when the dust makes contact with an oil seal, the piston rod is scratched, the oil seal i