Magnesium-lithium alloy, lightweight metal with high specific strength and ductility, is one of the most attractive structural and functional materials for the automotive, aerospace, and defense industries. However, its industrial applications are severely limited by its low strength, and low modulus. Hence, the preparation and processing (alloying, casting, heat-treatment and compounding), and research progress of various types of high-strength, and high-modulus casting Mg–Li alloys were summarized in this paper, which provides new ideas for researchers to develop high-strength and high-modulus Mg–Li alloys. Meanwhile, the advantages and limitation of preparation processes of different types were discussed, and the future development prospect and research direction were proposed. Finally, the development direction of the high-strength and high-modulus casting magnesium-lithium alloy is concluded.