Abstract: The influence of role sealing produced by plating Cu at low current density on the corrosion resistance of the anodized AZ31 magnesium alloy was studied. After anodization, AZ31 specimens were treated as a cathode with low current density in a traditional solution for Cu electroplating. The experimental results of SEM, EDS and XRD show that after such treatment at low current density, Cu is deposited in the porous layer of anodized film. The polarizing curves measured in 3.5% sodium chloride solution show that after plating Cu at low current density the corrosion potential of the anodized AZ31 magnesium alloy increases, and its corrosion current density reduces correspondingly, which indicate that the corrosion resistance of the anodized AZ31 magnesium alloy increases.