To study the protective effect of astragalus saponin extracts (AS) on kidneys of diabetic rats. Totally 32 diabetic rats induced by streptozotocin (STZ) were divided into AS high and low dose groups, the positive control group and the model group (DM group) and orally administered with 50 mg x- kg(-1) x d(-1) AS 200, 25 mg x kg(-1) x d(-1) valsartan, 10 mL x kg(-1) x d(1) physiological saline, respectively. Another 8 healthy rats were collected in the normal control group (NC group, physiological saline 10 mL x kg(-1). d(-1)). All rats were treated for consecutively 6 weeks. After the administration, the body weight was measured every week, the concentration of blood glucose was monitored on week 2, 4 and 6. The total urine and total urinary protein (U-TP) in 24 h were measured by the metabolic cage method on week 6; At the end of week 6, blood samples were collected from hearts to detect blood urea nitrogen (BUN), serum creatinine (Scr), uric acid (UA) , total cholesterol (CH) triglyceride (TG) by biochemical methods. Kidneys were collect to calculate the kidney hypertrophy index and observe the pathological sections. The laboratory results show that in the DM group, the blood glucose, metabolic cost in 24 h, kidney hypertrophy index, U-TP, BUN, Scr, UA, TG were significantly higher than that in the NC group (P < 0.01, P < 0.05) , with significant pathological changes; After the intervention with AS, the metabolic value in 24 h, kidney hypertrophy index, U-TP, BUN, Scr, UA, TG were significantly lower in the high dose group (P < 0.01, P < 0.05), and the kidney hypertrophy index, BUN, Scr, UA, TG in the low dose group were also significantly lower (P < 0.05), with slight reduction in renal pathological changes in both groups. In conclusion, Astragalus saponin extracts have a certain protective effect on kidneys of diabetic rats.