Apolipoprotein A II is a kind of human Apo A. Apo A is the protein part of lipoprotein, and there are various types of Apo A, Apo B, Apo C, Apo E and so on. Among them, each different apolipoprotein is divided into many different subtypes. Apolipoprotein A has many subtypes such as Apo AⅠ, Apo AⅡ and Apo AⅢ. Apolipoprotein A II is an important apolipoprotein in the human body, mainly involved in the synthesis of high-density lipoprotein in the human body. When the concentration of HDL is high, it is an effective lipoprotein to protect blood vessels, which can degrade LDL in human body and prevent cerebral thrombosis, coronary heart disease and other atherosclerotic diseases, and is a lipoprotein with protective effect on blood vessels. Therefore, a high level of Apolipoprotein AⅡ indicates that the human body has a lower chance of getting cerebral thrombosis and coronary heart disease, which is a useful Apolipoprotein for the human body.