Gynura divaricata acidic polysaccharide (GDAP) was extracted and purified from dry leaf of Gynura divaricata (Linn.) DC. Effects of successive lavage GDAP for 0, 7, 14 and 21 d with daily dose of 15, 37 and 60 mg·kg^-1on blood glucose content of diabetic model mice were analyzed, and differences in SOD activity and MDA content in serum and glycogen content in liver of mice were compared. The results show that with prolonging of successive administration time and increasing of GDAP daily dose, blood glucose content of diabetic model mice generally appears the decreasing trend. With successive administration for 14 and 21 d, blood glucose content of different GDAP treatment groups is generally lower than that of CK group (0. 9% NaCl injection with daily dose of 10 mL·kg^-1 ) but higher than that of T1 group (metformin with daily dose of 200 mg·kg^-1). In which, after successive administration GDAP for 21 d with daily dose of 37 and 60 mg·kg^-1 , blood glucose content of diabetic model mice is significantly or extremely significantly lower than that of CK group but significantly or extremely significantly higher than that of T1 group, while SOD activity in serum of diabetic model mice is significantly higher and its MDA content is significantly lower than those of CK group, but there is no significant difference with those of T1 group. Glycogen content in liver of diabetic model mice of different GDAP treatment groups is higher than that of CK group, but lower than that of T1 group. It is suggested that GDAP is the main hypoglycemic components in polysaccharide of G. divaricata leaf, and it has dose-effect relationship in hypoglycemic activity. Hypoglycemic mechanism of GDAP is probably related to improving antioxidant enzyme ability in the body, enhancing activity of scavenging oxygen free radicals, relieving liver damage, and increasing glycogen storage capacity.