The invention discloses a processing method of a rubber gasbag special for a petroleum drilling machine. The processing method comprises six process steps of refining rubber, rolling and cutting, pressing, forming, vulcanizing and packaging, wherein in the vulcanizing process step, liquid water is injected into the rubber gasbag by a high-pressure pump and the pressure is controlled by a pressuregauge, so that steam pressurizing for the traditional vulcanization is replaced, the internal pressure of the rubber gasbag during vulcanization is increased, the density of the rubber gasbag is increased, the product quality of the processed rubber gasbag is optimized; furthermore, a rubber gasbag automatic mold on a vulcanization machine is adopted during vulcanization production, and vulcanization temperature, time and pressure are adjusted, so that the mold in the production process can perform mold closing, mold opening and lifting positioning accurately, and the problem that time and power are consumed by manual operation is solved; in addition, the liquid water is low in cost and can be recycled, so that the production cost of enterprises can be obviously reduced.