Oat β -glucan is a kind of water-soluble dietary fiber. Because of its viscosity, it hinders the digestion and absorption of starch, protein and other substances, and can proliferate beneficial bacteria in the digestive tract, so it can produce some extremely beneficial physiological functions for the human body: it can significantly reduce blood lipid and blood sugar, improve immunity, and maintain intestinal microecological environment. In addition, it can also speed up the identification of immune cells in the population. Respond to bacterial infection, control the site of bacterial infection, and make the infected surface recover as soon as possible; As an effective component of cosmetics, it can improve the anti-allergic ability of skin, activate immune function and delay skin aging. Oat water-soluble dietary fiber and oat dextran can effectively reduce postprandial blood glucose concentration and insulin level, lower cholesterol and prevent cardiovascular diseases. Oat fiber food is easily absorbed by human body, and because of its low calorie, it is not only beneficial to lose weight, but also suitable for dietotherapy needs of patients with heart disease, hypertension and diabetes.