This study was carried out to investigate the antidiabetic and antioxidative effect of Lycii fructus in the Streptozotocin(STZ)-induced diabetic rats. The effective fractions were prepared as a form of organic solvents of $CH_{3}(CH_{2})_{4}CH_{3}$ $CHCI_{3}$, EtOAc, BuOH and $H_{2}O$ fractions prepared from the EtOH extract of Lycii fructus and The diabetes were induced by an tail-intravenous injection of STZ with a dose of 45 mg/kg dissolved in citrate buffer. The various fractions of Lycii fructus were orally administrated once a day for 7 days. The contents of serum glucose, and triglyceride in the $CHCI_{3}$ fraction and hepatic lipid peroxidation in the EtOAc, BuOH and $H_{2}O$ fractions treated rats were significantly decreased when compared to those of the STZ-control group In addition, an activity of hepatic GST in the BuOH fraction treated rats was significantly increased compared to that of the STZ-control group. whereas, activities of hepatic catalase, GSH-Px in the BuOH fraction treated rats were significantly decreased compared to those of the STZ-control group. Meanwhile, The content of hepatic glycogen and avtivity of hepatic glucokinase in $CHCI_{3}$ fraction treated rats were significantly increased, but activity of glucose-6-pase was significantly decreased in the $CHCI_{3}$ fraction treated rats. In conclusion, these results indicated that the BuOH fraction of Lycii fructus was effective for the antioxidation, and also the $CHCI_{3}$ fraction of Lycii fructus was effective for the antidiabetes in the STZ-induced diabetic rats.