The invention relates to a hydraulic headstock gear convenient in overhauling. The hydraulic headstock gear comprises a power pack and an oil cylinder body, wherein the power pack comprises a signal part and a power part; a first supporting plate is fixedly connected with the two sides of the bottom surface of the power pack; a second supporting plate is fixedly connected with the two sides of the oil cylinder body; the middle part of the bottom surface of the power pack is shaped like an arc to be matched with the outer round upper surface of the oil cylinder body; a plurality of first through holes are formed in the first supporting plate; a plurality of second through holes are formed in the second supporting plate; the first through holes and the second through holes are in one to one correspondence; the first through holes and the second through holes are fixedly connected through bolts. In the invention, the power pack is integrated on the traditional hydraulic oil cylinder to form a complete hydraulic headstock gear, so that the structure form is optimized, the whole layout space is saved, and the hidden dangers due to complicated pipelines are reduced. during the later routine maintenance and overhauling, the power pack can be separated from the oil cylinder body, so that the maintenance is easier, and the work amount is less.