The present study was carried out to investigate the preventive effect of Epimedii Herba combined Samgijiwhang-Tang(SJTE) on streptozotocin(STZ)-induced diabetic nephropathy. SJTE was given to rats with oral administration. The experimental animals were divided into normal group of rats, control group of STZ-induced diabetic rats, and sample group with SJTE administration. Experimental diabetic nephropathy was induced by the injection of STZ(60mg/kg) to the rat via the peritoneum. The effect of SJTE on STZ-induced diabetic nephropathy was observed by measuring the serum level of insulin, glucose, creatinine and BUN. Urine secretion of albumin for 24 hours and urine level of glucose measures too. Anti-oxidative stress of STZ administration in living body was estimated by measuring lipid peroxide in cortex of kidneys. STZ induced increase of serum glucose. creatinine, urine albumin secretion and renal cortical lipid peroxidation were lowered by SJTE administration. In conclusion, the SJTE treatment showed protective effect on rat diabolic nephropathy model, and action mechanism of the effect was thought to be concerned with internal glucose metabolism.