Locking device for oil cylinder

The utility model discloses a locking device for an oil cylinder, and belongs to the technical field of hydraulic execution elements. The locking device for the oil cylinder comprises an oil cylinder body, locking mechanisms and an ejector block, a piston rod is arranged in the oil cylinder body, the locking mechanisms are located on the surfaces of the two sides of the oil cylinder body and fixedly connected with the surfaces of the two sides of the oil cylinder body, telescopic rods are arranged in the locking mechanisms, and the ejector block is fixedly connected with the piston rod. And a dustproof ring is arranged on the surface of the rear end of the top block. The hydraulic oil cylinder solves the problems that an existing hydraulic oil cylinder is poor in locking effect and dustproof effect, after the whole hydraulic oil cylinder is used and the piston rod is reset, the dustproof ring on the surface of the rear end of the ejector block makes contact with an inlet and an outlet of the piston rod, the b