Dairy cow haemolactia is a disease caused by the hyperemia of blood vessels in the tissues around the milk transfusion tube and the acinus in the milk of the cow,and the obvious expansion and rupture of the blood vessel wall,which causes the hemoglobin or red cells in the blood vessels to enter the milk transfusion tube and the acinus,so that the secreted milk is mixed with red blood and blood clots. Generally,the disease can be cured by improving the feeding and management conditions,but the serious cases need to be treated with drugs,otherwise it will induce other diseases such as mastitis of dairy cows,resulting in the decline of milk production and even death of dairy cows,and bring serious economic losses to the dairy industry.Through in-depth analysis of various causes of cow haemolactia,such as mechanical injury,poisoning,infection,etc.,this paper expounded the clinical symptoms and diagnostic methods of the disease,put forward prevention and treatment measures by different means such as western medicine and Chinese and Western medicine,and provided theoretical support for the healthy breeding of cows with examples.