According to the low current efficiency of magnesium sacrificial anode, magnesium sacrificial anode material with gadolinium addition was investigated. The electrochemical properties of the material were measured by constant current method. The microstructure and composition of the anode material were characterized by metallurgical microscope and energy spectrum analysis. The results show that addition of gadolinium in magnesium sacrificial anode can refine grain size, change second-phase distribution, maximize current efficiency, and minimize potential of magnesium sacrificial anode. When the addition of gadolinium reaches 0.1%, the highest current efficiency is reached as much as 65.32%, which increases by 10%, compared with magnesium anode without gadolinium addition.