Abstract: Objective: To investigate the hypoglycemic effect and mechanism of a neutral homogeneous polysaccharide from Acanthopanax trifoliatus ( L.) Merr. ( ATP1-1) on typeⅠdiabetic mice induced by STZ.Methods: TypeⅠdiabetic animal model of C57BL/6 mice was established by multiple intraperitoneal injection of low dose streptozotocin ( MLD-STZ) .Diabetic mice were randomly divided into hyperglycemia group, positive control group of metformin, high-dose and low-dose groups of ATP1-1.Normal mice were used as blank control, 10 mice for each group.The above components were administered intragastrically for 4weeks.Hepatic glycogen and fasting blood glucose were determined at the end of administration.The mRNA expression of GK, G6 Pase, GLUT2 were also observed by RT-PCR assay. Results: Compared with hyperglycemia group, FBG levels of the drug groups ( high-dose and low-dose of ATP1-1) were decreased after 4 weeks' administration ( p < 0.05) , meanwhile, hepatic glycogen content of the drug groups were increased ( p < 0.05) .The inhibition rate of blood glucose for 40 mg·kg^-1 dose group was 29.4%.RT-PCR results showed that ATP1-1 could increase the mRNA expressions of GK and GLUT2 ( p < 0.01) , while reduce the mRNA expression of G6Pase ( p < 0.05) . Conclusion: ATP1-1 could decrease the blood glucose of type I diabetic mice, regulation of glycometabolism might be one of the mechanisms.