The Purpose of this study was to investigate the effect of dietary sea tangle in diabetic rats treated with streptozotocin(STZ). Four groups of rats (Sprague-Dawley male rats,180-200g) were normal rats fed control diet(C), diabetic rats fed control diet(CD), normal rats fed sea tangl diet(T), and diabetic ,rats fed sea tangle diet(TD), diabetes was induced by single injection of streptozotocin(60mg/kg B.W.). High density lipoprotein(HDL) of T and TD group were higher than other groups(C and T groups). And the weekly change of blood sugar was decreased in the 3th and 4th weeks. But serum triglyceride (TG) of diabetic rats fed sea tangle diet(TD) was lower than diabetic rats fed control dlet(CD). Activity of hepatic microsomal Glucose 6-phosphatase(G6Pase) was significantly increased CD and TD groups higher than C and T groups. Hepateic glutathione S-transferase(GST of T, CD and TD groups were significantly lower than C group(p<0.05), glutathione peroxidase (GPX) of T and TD groups were significantly higher than C and CD groups(p<0.05).