Abstract: Milk is an ideal protein supplement, 80% of which is casein. Casein, as the main allergen in milk, seriously affects the nutritional supplement choice of patients with milk allergy. Studies have shown that the structural characteristics of casein play a vital role in its allergenicity. To deeply explore the relationship between its structural characteristics and allergenicity, it is necessary to use appropriate purification methods to obtain high-purity casein. From the two perspectives of the preliminary separation of micellar casein and the purification of casein components, this article focuses on the research progress of the purification of bovine casein, and describes the structural characteristics of bovine casein and its influence on allergenicity. It provides theoretical and technical support for the study of using protein modification technology to reduce or eliminate the allergenicity of casein.