Objective:To investigate the influence and mechanism of “Qinghua Gushen Paidu Decoction” on renal tubular epithelial mesenchymal transition in unilateral ureteral obstruction (UUO) rats  Methods:A rat model of renal fibrosis was prepared by unilateral ureteral obstruction. 108 SD rats were randomly divided into sham operation group(n=18),UUO model group(n=18),“Qinghua Gushen Paidu Decoction” high dose(n=18), middle dose(n=18) and low dose(n=18) groups, and Lotensin treated group(n=18).The 6 groups of rats were treated with corresponding drugs,once a day. Mental conditions,activities,hair color,shape of stool,and body weight were observed during administration. At 7, 14, and 21 days, 6 rats in each group were randomly sacrificed. Then 24h urine was collected and 24h urinary protein (24h UP) was detected. Serum blood urea nitrogen(BUN)and serum creatitine(Scr) were also tested. The left surgery renal tissue were collected for pathological examinations. The pathological changes of the obstruction renal tissue were examined by Hematoxylin and eosin staining (HE). The protein expressions of TGF-β,1, and α-SMA were detected by immunohistochemical staining  Results:Compared with the sham-operation group,the general condition of the rats was poorer in the other groups,their body weight grew slower,and serum levels of BUN,Scr increased(P,<,0.05),the renal tubular damaged comparatively serious(P,<,0.05),protein expression levels of TGF-β,1,α-SMA increased in the renal tissue(P,<,0.05). The renal interstitial fibrosis degree was gradually aggravated along with the ureteral obstruction time. Compared with the model group,the serum levels of BUN,Scr decreased(P,<,0.05)in the rats of the TCM groups (high, middle and low dose groups) and Lotensin treated group, the condition of the damage of the renal tubular get better(P,<,0.05), protein expression levels of TGF-β,1,α-SMA decreased(P,<,0.05). Compared with the Lotensin treated group, no significant difference in effect on indexes was observed between TCM groups and Lotensin treated group(P,>,0.05). No significant difference in effect on indexes was observed between the high, middle and low dose groups(P,>,0.05)  Conclusion:“Qinghua Gushen Paidu Decoction” may inhibit the EMT by down-regulating the expression of TGF-β,1,α-SMA, can protect the kidney and ameliorate renal interstitial fibrosis.