There are three oil cylinder covers used in different locations. First is cushion oil cylinder cover. It belongs to the technical field of hydraulic oil cylinder parts and comprises the oil cylinder cover body. The function of cushion oil cylinder cover is to solve the technical problems of hydraulic oil loss and short service life of the sealing ring in the prior art, so that it can extend the lifespan of the oil cylinder piston. Second is improved oil cylinder cover. It comprises the cover body, bottom cap, fixing holes and the oil leaking hole. The function of improved oil cylinder cover is more convenient to collect leaked oil. Third is conveniently-installed oil cylinder cover which is used to a cover body, bottom cover, fixing holes and handle parts. Those schemes are simple in structure and manufacture.