Objective：To observe the clinical effect of Jiangtang Baoshen prescription combined with western medicine therapy for diabetic nephropathy at stageⅢandⅣ.Methods：Divided 60 cases of patients with diabetic nephropathy into the treatment group and the control group randomly，30 cases in each group.Both groups receivedthe routine therapy of diabetic nephropathy，while the treatment group additionally received Jiangtang Baoshen prescription orally.The course in both groups lasted for 60 days.Compared the clinical effect between the two groups，and observed Chinese medicine(CM)syndrome scores，renal function indexes[serum creatinine(SCr)and blood urine nitrogen(BUN)]，urine fibronectin(FN)，urinary type IV Collagen(Col- Ⅳ)，and quantitative urinary protein in 24 hours.Results：After treatment， the total effective rate in the treatment group was higher than that in the control group(P＜0.05).CM syndrome scores in both groups were lower than those before treatment， and CM syndrome scores in the treatment group were lower than those in the control group，differences being significant(P＜0.05).Levels of SCr and BUN in the control group were not significantly decreased when comparing with those before treatment(P＞0.05).SCr levels in the treatment group were lower than those before treatment(P＜0.05)and were also lower than those in the control group(P＜0.05)，while the comparison of BUN levels after treatment with those before treatment showed no significance in differences(P＞0.05).Compared levels of urine FN and urinary Col-IV in the control group before and after treatment，there was no significance being found in differences(P ＞ 0.05).Quantitative urinary protein in 24 hours of the control group was less than that before treatment(P＜0.05).Those three indexes of the treatment group after treatment were all lower than those before treatment，and were all lower than those of the control group.Conclusion：Jiangtang Baoshen prescription can protect renal function of patients in their early stage and improveclinical symptoms effectively.Its mechanism may be to relieve excessive glomerular extracellular matrix accumulation，improve the clinical symptoms and delay the deterioration of renal function by reducing levels of FN and Col-IV in urine.