Magnesium and its alloys, which have abundant storage in nature, rank third among the whole list of metal elements in the earth crust. As one of the lightest metal structure materials, the density of magnesium alloy is 1. 74 g/ cm3, and the ratio of specific strength is up to 134, with good toughness, strong shock absorption, low heat capacity, good performance, excellent diecutting performance and so on, and therefore magnesium alloy has a wide range of applications in the military, aerospace and automotive and other fields for its characteristics, such as low density, high strength, specific rigidity, high damping ability, better casting property and so on. The preventive disposing on magnesium alloy‘s surface is very important for improving its low corrosion resistance, prolonging its service life and expanding the application field. The principles, advantages and current existing problems of the surface treatment technology used for magnesium alloys were reviewed in detail, and the principle, advantages and existing problems of chemical conversion processing, electroless nickel plating, chemical plating, anodic oxidation, micro-arc oxidation, laser surface treatment, thermal spraying, and organic coating were introduced. The surface modification techniques including vapor deposition, ion implantation and Dacromet coatings were briefly introduced, finally the development trend of magnesium alloy surface modification was analyzed and it was proposed that magnesium alloy surface modification technology should develop towards low pollution, low cost, high efficiency, and multi-technology.