Abstract: Aluminum alloy, with its excellent characteristics such as high specific strength, strong corrosion resistance, and good formability, is widely used in high-tech fields such as aerospace, transportation, and electronic appliances, making it one of the most widely used metallic materials today. The purity of molten aluminum has a significant impact on the regulation of alloy composition and microstructure, largely determining the performance of aluminum alloys. The occurrence forms, migration mechanisms, and purification methods of impurities in molten aluminum represent key challenges and important research topics in the primary and recycled aluminum industries. This paper systematically reviews the main types of impurities in molten aluminum and their detrimental effects, categorically elaborates on the principles and research progress of adsorption purification, non-adsorption purification, and composite purification methods, analyzes the characteristics, applicability, advantages, and disadvantages of different purification techniques, and identifies current technical bottlenecks as well as potential future research directions, providing a reference for the study of deep purification of molten aluminum.