As the lightest metal, magnesium alloy can partly replace some steel materials in achieving light weight. Since magnesium alloy features in high specific strength, specific stiffness, good shock absorption, noise reduction and favorable machinability, it is now increasingly demanded by the market. However, owing to low electric potential, it was easily subject to galvanic corrosion galvanic corrosion with other metals. A ceramic layer-like coating of excellent comprehensive performance could be prepared on the surface of magnesium alloy surface by micro-arc oxidation. In this way, corrosion resistance, wear resistance and high-temperature resistance were all greatly improved. Therefore, micro-arc oxidation technology was developed rapidly on surface treatment of magnesium alloy. For this purpose, current research on mechanism of micro-arc oxidation was introduced firstly, several main stages of micro-arc oxidation process and their main functions were summarized; then main factors affecting preparation technology of magnesium alloy micro-arc oxidation ceramic film, especially effects of electrical parameters, electrolyte and oxidation time on the film structure, morphology and performance were elaborated in details; finally several key problems now present in the magnesium alloy micro-arc oxidation process, and solution and even application foreground were expected as well.