Abstract: To investigate the effects of oat β-glucan on type Ⅱ diabetic mice caused by STZ, 100 male Kunming mouse (20±2) g were divided into two groups:normal control group and model group. Diabetic mice were divided into 5 groups ( each group, n=15): model control group, high dose β-glucan group, median dose β-glucan group,low dose β-glucan group, Metformin hydrochloride Tablets group,which were fed different diets for 6 weeks. Oral glucose tolerance test was carried out six weeks later, serum insulin concentions,liver glycogen and muscle glycogen were measured,insulin activity indexs were calculated at the end of the experiments. The results showed that the groups of different doses of β-glucan significantly lowered fasting blood glucose. Oat β-glucan could significantly stimulate insulin secretion, improve insulin resistance and glucose tolerance ability,promote synthesis of liver and muscle glycogen. The best was the group high dose β-glucan group(2 000 mg/kg·bw)among all of the oat β-glucan groups.