Objective To explore the effect of Coprinus comatus polysaccharide (CP) on hypoglycemia in rats with type 1 diabetes mellitus (DM) induced by streptozotocin (STZ). Methods Forty male Wistar rats were selected and 30 rats were injected intraperitoneally with 50 mg/ kg STZ to establish a diabetic rat model. Rats with successful modeling were randomly divided into polysaccharide, model and positive drug groups. After 60 days of administration in each group, sugar tolerance test was performed. next day,the serum was taken to detect insulin, urea nitrogen, serum creatinine, triglyceride, and total cholesterol. The liver and kidney were taken out to weigh and their supernatant was used to detect the superoxide dismutase and malondialdehyde content. Pathological changes in the kidney and liver tissues were observed by hematoxylin-eosin (HE) staining. Results Compared with the model group, CP increased body weight, serum insulin, SOD activity and MDA, and significantly reduced blood glucose blood urea nitrogen, serum creatinine, triglyceride and total cholesterol in the diabetic rats ( P <0. 01). The shape of the glomeruli was regular with a clear structure and reduced vacuoles in the hepatocytes. Conclusions Coprinus comatus polysaccharide displays good antioxidant activity in STZinduced diabetic rats and has a role in lowering blood glucose.