The effect of ⁶⁰Co-γ ray irradiation on hypoglycemic activity of polysaccharides from Inonotus obliquus was explored. The polysaccharides of Inonotus obliquus under the irradiation doses of 5, 10, 20 and 30 kGy were extracted and their contents were determined. The experiment was performed on a mouse model of type I diabetes induced by streptozotocin (STZ) according to the grouping dose. The body weight, food intake and water intake of the mice were measured every day during the experiment, blood glucose levels were measured every 7 days, and glucose tolerance test (OGTT) was performed 30 days later. Blood samples were dissected and analyzed for glycated hemoglobin (GHb), total cholesterol (TC), triglyceride (TG) levels and organ coefficients. The results showed that when the irradiation dose was 20 kGy, the polysaccharide content was the highest; The irradiated polysaccharides of Inonotus obliquus at the same dosage can be more effective than the unirradiated polysaccharides in relieving the symptoms of liver and kidney enlargement in diabetic mice (P＜0.05) without burdening the heart and spleen function of the mice; At the same time, it has a faster effect on reducing blood sugar (P＜0.05). Therefore, the polysaccharides of Inonotus obliquus after irradiation treatment has a good hypoglycemic effect, which provides a reference for the in-depth exploration of irradiation treatment the polysaccharides of Inonotus obliquus to lower blood glucose.