Milk allergy is a severe foodborne illness. This disease usually occurs due to the interaction between milk proteins and their metabolites, leading to immune dysfunctions in the body. Milk allergy is gradually becoming a major global public health problem, especially for infants and young children. This review elaborates the mechanism behind the allergenicity of bovine casein, α-lactalbumin and β-lactoglobulin, introduces the technologies that have currently been successfully used in the detection of bovine milk allergens, discusses their advantages and disadvantages in practical applications, and systematically summarizes the physical, chemical and biological modification methods to reduce the allergenicity of bovine milk proteins. Finally, some hypoallergenic dairy products developed by researchers in recent years are listed, and the future directions for the development of dairy allergen modification and the future prospects of hypoallergenic dairy products. This review is expected to provide a theoretical basis and research ideas for the development of hypoallergenic dairy products in the future.