To study on hypoglycemic effects of the combination of Rhizoma Coptidis and Radix Puerariae Lobatae on rats.Methods:SD rats were selected.Streptozotocin was injected into abdomen for molding.Rat with successful molding(blood sugar ≥ 11.1 mmol/L were randomly divided into the following groups:blank control group，model group,metformin group,Rhizoma Rhizoma Coptidis and Radix Puerariae Lobatae groups of high-dose,middle-dose and low-dose.After giving medicine for 21 days,blood sugar，the insulin sensitivity index，CAT、SOD、GSH-Px and MDA in serum of high blood rats,were observed in Rhizoma Coptidis and Radix Puerariae Lobatae groups of high-dose,middle-dose and low-dose.Results:The high-dose,middle-dose and low-dose of Rhizoma Coptidis and Radix Puerariae Lobatae could apparently reduce blood sugar value of hyperglycemia rats,significantly improved the insulin sensitivity index，significantly increased the vitality of CAT、GSH-Px,SOD in rats and lowered the content of MDA.Conclusion:The high-dose,middle-dose and low-dose of Rhizoma Coptidis and Radix Puerariae Lobatae could apparently reduce blood sugar value of hyperglycemia rats,improve antioxidant ability of rats and reduce insulin sensitivity index of rats.