In order to improve the effect of prevention and treatment of cow mastitis,this paper studied the diagnosis,treatment and comprehensive prevention of cow mastitis. Starting from the causes of mastitis,the causes of mastitis were summarized as pathogenic microorganisms,seasonal changes,environmental conditions and self-induced factors,which were divided into clinical mastitis and recessive mastitis,and different types of mastitis diagnosis methods,treatment methods and comprehensive prevention methods were proposed. The diagnostic methods of dairy cow mastitis included clinical symptom diagnosis,etiology detection, milk cell detection, physical detection,chemical detection,milk conductivity detection,etc.,and the detection results were highly accurate.The treatment methods included western medicine therapy,Chinese medicine therapy and other therapies,all of which could achieve good therapeutic effect. A number of comprehensive preventive measures were put forward,such as improving feeding environment,strengthening feeding management,strengthening milking norms,doing a good job in scientific prevention,reducing stress reaction and rational drug prevention. Dairy cow mastitis is a common disease in dairy cow breeding. During the breeding period,timely diagnosis and accuracy of diagnosis results should be ensured,corresponding treatment methods should be adopted,and comprehensive prevention should be done,so as to provide theoretical guidance and basis for reducing the incidence and improving the control effect,and promote the development of dairy cow breeding in China.