Objective: To study the preventive effect of lycopene (LP) on hyperglycemia in alloxan-induced diabetic rats, and reveal its possible mechanism.Method:Forty Sprague-Dawley rats were randomized into 5 groups:three groups of LP at doses of 5, 20, 50 mg(/kg bw ?d)for 15d, one control group and one model group of salad oil. Then alloxan (ALx) were injected intraperitoneally to the rats at dose of 150 mg/kg bw. At D4 and D14 after ALx injection, an oral glucose tolerance test (OGTT) was performed and body weight was measured, and at D14 GSP, FINS, NEFA, SOD,GSH-Px and MDA in liver were also determined . Results:Compared with the indices in group with ALX injection only,both the 2h blood glucose and GSP in group with medium-dose LP decreased significantly(P