Abstract: This paper covers the current situation and research progress of additives appled to micro-arc oxidation of magnesium alloys in recent years. According to the existing state of additives in the electrolyte, they are divided into cationic additives, anionic additives and non-ionic additives. The action mechanism of the additives during the micro-arc oxidation process was analyzed, and the effects of different kinds of additives on the properties of oxidation films were summarized. The development prospect of the additives appled to micro-arc oxidation was mentioned. It is expected to provide reference for researchers to improve the properties of micro-arc oxidation films.