The cerium-based coatings have attracted increasing attention for modifying Mg surface in biomedical applications due to their corrosion protectiveness and potential biological effects. However, their anti-corrosion mechanisms have not been fully understood. In this work, the corrosion resistance of anodic electrodeposited cerium-based oxides coating on Mg alloy was investigated in Hanks’ balanced salt solution. The obtained results demonstrate that the strengthened precipitation of protective calcium phosphate products on this coating results in its enhanced anti-corrosion nature. These findings enrich the understanding on anti-corrosion mechanisms of the cerium-based coating and point out its prospect on Mg alloys for bone implants.