Abstract: The A1/A2-β-casein allele of dairy cows determines the type of milk they produce. A2 milk is popular because it is more similar to breast milk. The detection of A1/A2-β-casein allele plays an important role in the grouping feeding,breeding and trading of A2 dairy cows,and it is of great significance to the breeding of A2 dairy cows. In this paper,the reported methods of polymerase chain reaction-restriction fragment polymorphism（ PCR-RFLP）,allele-specific PCR（ AS-PCR）,TaqMan probe,rhAmp and high-resolution melting curve analysis（ HRM） for the identification of A1/A2 alleles in dairy cows were summarized. The advantages,disadvantages and applicability of these methods were analyzed in order to provide scientific basis and theoretical reference for the selection of A1/A2 allele genotype identification methods and the promotion of the research and development of new methods.