Abstract: The effect of rare earth Ce content on the microstructure and corrosion properties of Al-5.0 Mg-2.2 Si-0.6 Mn alloy was studied. The results show that the addition of Ce element can significantly affect the microstructure of the alloy.With the increase of Ce element, the secondary dendrite spacing of the alloy decreases first and then increases. Ce element can improve the corrosion resistance of the alloy. With the increase of Ce element content in the alloy, the corrosion resistance of the alloy increases first and then decreases. When the content of Ce element is 0.15 wt%, the alloy has the best corrosion resistance. When the Ce element is added too much, the coarse brittle rare earth phase formed in the alloy seriously reduces the corrosion resistance of the alloy.