Abstract: The straightness accuracy, run-out tolerance, surface roughness and corrosion resisting property of 4Cr9Si2 and 21-4N materials valves were tested and compared after surface chemical treatment and shot blast treatment to remove the surface oxide. The result showed that chemical treatment technology overcomed effectively the shortcoming of shot blast treatment technology including large deformation of workpiece, surface roughness and low corrosion resisting property. Therefore chemical treatment technology is more adaptive to production than blasting shot and it can improve production quality.