Abstract： Objective To observe the effect of Bailing on renal protection and expression of connective tissue growth factor(CTGF) in the rat models with 5/6 nephrectomy,and to investigate the antifibrosis mechanism of Bailing. Methods Fifty SD aduh rats were used.8 of them were randomly assigned to sham operation group(group A),and others underwent 5/6 nephrectomy.According to serum creatinine (Scr) levels in 3 weeks after operation,the nephrectomized rats were randomly assigned to 4 groups(group B,C,D,E),The rats in group B were operated and untreated.Group C received Cordyceps sinensi (2.0 g·kg-1·d-1) for treatment.Group D,E received different doses of Bailing(2.0 g·kg-1·d-1,3.0 g·kg-1·d-1 respectively) for treatment.When 4 weeks meter the operation,group C,D,E were intragastrically perfused with drugs for one month respectively.At the end of the experiment,Scr,BUN,renal histopathology were detected and immunohistoehemistry was performed to examine the CTGF,alpha smooth muscle actin (α-SMA),ceil keratinl8(CK-18).Results In group B,the Scr,BUN,renal pathological lesion and the expression of CTGF,α-SMA were obviously higherthan those in group A(P<0.01),while in group C,D,E,these index were significantly improved as compared to group B(P<0.05).Conclusion Bailing can improve fibrosis and protect the remnant kidney function.The mechanism of Bailing in delaying chronic renal failure may be related to the down-regulated expression of CTGF in the remnant kidney.