A gearbox which is developed independently and used for 200 km/h passenger locomotive is introduced. The analysis of gear and box is carried out respectively by the CAD and finite element analysis,and the high reliability of the gearbox is confirmed. The gear blanks are forged from 18 CrNiMo7-6 alloy steel which is electroslag remelted. In order to ensure the reliability and smoothness during the gear meshing,the carburizing,quenching,shot peening and profile correction are added in the process of gear forming. The material of the gearbox is adopted aluminum alloy instead of the ductile iron,not only meet the requirements of lightweight design,but also contribute to the cooling of the gearbox. During the type test,the gear box running smoothly,the temperature rise of the bearings is also meeting the requirement.