Diabetic nephropathy (DN) is the most frequent cause of end-stage renal disease. The activation of the renin-angiotensin system (RAS) and lipid disorders are major risk factors in progressive chronic kidney disease. Inhibition of the RAS is one of the most widely used therapies to treat chronic kidney disease. But its effect is not sufficient, and lowered hyperlipidemia is required. Most of medications for hypertension have effects only on the blood pressure in DN. This study is to evaluate the influence of irbesartan on blood lipid, kidney function, and the pathological change of kidney, liver, and adipose tissue.Six-week old db/db mice were randomly assigned to control group and irbesartan group. Mice in irbesartan group were fed 40 mg/kg irbesartan each day. Eight weeks later, blood lipid, kidney function, and the pathological change of kidney, liver, and adipose tissue were measured.The results indicated that the blood lipid, uric acid, urea nitrogen, and creatinine of db/db mice increased significantly. There are obvious vacuolar degeneration and ballooned hepatocytes around the central vein of db/db mouse liver. Kidney biopsy found glomerular hypertrophy of glomerular, mesangial thickening, and vacuolar degeneration. Irbesartan can decrease the blood pressure, blood lipid, and kidney lipid. But it has no effects on blood glucose and liver lipid. It can improve the function and pathological change of kidney of db/db mice. But it has no effects on pathological change of adipose tissue and liver.Irbesartan can decrease blood lipid and protect the kidney of db/db mice, and is a good choice of treatment for diabetic nephropathy.