Metal inert gas (MIG) welding provides the advantages of a high deposition rate, high thermal efficiency, and facilitates readily automated, efficient production. Magnesium alloys have broad application prospects in transportation, aerospace and other industries due to their high specific strength and good damping performance. MIG welding is a suitable welding method for magnesium alloys, and there have been a large number of researches and technological developments. This paper introduces the research status of MIG welding of magnesium alloys, reviews the related research on droplet transition mode, microstructure, and MIG hybrid welding, and looks forward to the future research directions of MIG welding of magnesium alloys.