Extrusion process is an advanced production technology, especially suits for the manufacturing process of fine-pitch gear. To meet the demand of the tooth form of gear shaft and quartet technology, the process scheme of gear shaft extrusion was confirmed and once-molded gear shaft extrusion die was designed. Extrusion die structure was better designed and analyzed in terms of manufacturing process, and the precautions for the use of die were emphasized. Practice proves that compared with previous products，the movement stability of the transmission mechanism of the full automatic washing machine equipped with gear shaft produced by cold extrusion process is improved by 6.5%,the noise level is reduced by 10% and the service life  is  extended by 18.5%.