Abstract： Objective To explore the mechanisln of action of Jianpiyishen Decotion on renal fibrosis and provide experimental evidence for chnieal application.Methods The Wistar male rats were randomly divided into four groups.They were normal control group(N group),model group(M group),low dose treatment group(L group)and high dose treatment group(H group).AⅡanimal models were made of CRF with subtotal renal ablation except the N group.Interference began at one week after operation.After being interfered for 8 weeks,blood serunl and nephridial tissues were taken out.Serum urea nitrogen(BUN)and creatinine(Scr)and fibronectin(FN)were detected.Results In N group。There were light expression in renal tubniointerstitial substance,cellula epithelialis basal meulbnule and Vascular smooth muscle.In M group,FN was strong expressed in renal tubulointerstitial substance and renal tubde,and also in glomerular mesangium.There was significant difference between N and M group(P<O.01).FN was medium expressed in renal tubuloinlerstitial substanceand renal tubule in L and H group.The expression of FN in L group was higher than that of N group(P<0.01)and lower than that of Mgroup(P<O.01).The expression of FL in H group was lower than that in L group(P<O.05).Condusion Jianpiyishen decotion can decrease eerum BUN and Cr ofCRF rats,restrain the expression of FN in kidney tissue.And it indicates that Jianpiyishen decotion is an effective herbal prescription for the treatment of CRF.The mechanism may be because it can restrain the expression of the cell factor such as FN in rats'kidney,and delay the progress of renal fibrosis and CRF.