Abstract: In order to solve the problems of poor corrosion resistance and rapid degradation of AZ31B magnesium alloy in human environment, a mechanical hammering surface modification method was proposed. In order to reveal the influence mechanism of mechanical hammering on the corrosion resistance of AZ31B magnesium alloy surface, the X-ray diffraction pattern of AZ31B magnesium alloy was analyzed and calculated, and the corrosion resistance of AZ31B magnesium alloy before and after hammering was characterized by electrochemical workstation and Zeiss microscope. The results show that after the mechanical hammering treatment, the surface grain size of the material is minimized to 38.55 nm, the corrosion current density is reduced by 93.92%, and the smaller the grain size, the better the corrosion resistance, which indicate that the mechanical hammering can effectively improve the corrosion resistance of AZ31B magnesium alloy.