It has been known that the lack of excellent corrosion resistance is the key problem restricting the wide application of Mg-Li alloys. Based on a quantity of literature about corrosion behavior of Mg-Li alloys, this review elaborates the factors affecting the corrosion behavior of Mg-Li alloys and the processing methods for improving corrosion resistance. The corrosion characteristics of Mg-Li alloys are described firstly. Then, it is explained that the grain size, orientation, second phase, and surface film strongly influence corrosion performance, which can be tailored by alloying, plastic deformation, and heat treatment. Further in-depth discussion about the corrosion mechanisms for Mg-Li alloys was also presented. Finally, important points of improving corrosion resistance are suggested.