The invention provides a gear shaft forging process. The gear shaft forging process comprises the steps that S1, raw materials are smelted through an electric arc furnace or a converter, a refining furnace and a vacuum degassing furnace to form steel ingot die casting; S2, earlier stage treatment is carried out; S3, heat treatment is carried out on the steel ingot die casting subjected to earlier stage treatment, and the heat treatment mode is controlled cooling, spheroidizing annealing, annealing, normalizing and high-temperature tempering; S4, forging treatment is carried out on the steel ingot die casting; S5, the forge piece is cooled to 400-450 DEG C, and then annealing treatment is carried out; and S6, rough turning, ultrasonic flaw detection and mechanical property testing are carried out on the forge piece, and finally a finished product is put in storage. The problems that the mechanical performance of a blank is reduced and forging damage of the forge piece is increased due to improper heat treatment after the blank is formed can be solved, the qualified rate of a finished product is high, the service life is long, the technological process is simple, operation is convenient, machining uniformity is good, material loss is small, the obtained product is good in mechanical performance and stable in structure, the manufacturing cost is reduced, and the production efficiency and benefits are improved.