The invention belongs to the technical field of forging equipment and particularly relates to a cooling device for gear forging machining. A bracket is fixedly mounted on a workbench. A hollow layer in a pressing plate on the bracket is connected with a water storage tank. Multiple first spray heads are arranged on the upper surface of the inclined pressing plate and are the spray heads made of metal. A one-way water outlet hole is formed between each first spray head and the pressing plate. Hollow protective plates are fixedly mounted on the two sides of the pressing plate and communicate with the pressing plate. Multiple second spray heads are arranged on the inner side of each protective plate. An inductor is arranged on each second spray head. An arc-shaped plate is arranged below the pressing plate. A first rotary shaft is arranged on the arc-shaped plate in a penetrating manner. A through hole is formed in the arc-shaped plate. A baffle inclining towards the arc-shaped plate is arranged on the position, in contact with a rack, of the lower end of the pressing plate. The cooling device solves the problems that the cooling speeds of a gear hub and the rim of a gear are different, workpiece residual stress-strain elimination speeds of the gear hub and the rim of the gear are different, consequently the gear deforms easily, and the dimensional precision of the gear is influenced.