Objective：To observe the effect of Yiqi Huayu Huatan preparation and their mixed preparation on renal interstitial fibrosis in rats with unilateral ureteral obstruction（UUO） and investigate the possible mechanism. Methods：Totally 42 female sprague-dawley（SD） rats were randomly divided into sham operation group，model group，telmisartan group，Yiqi group，Huayu group，Huatan group and Yiqi Huayu Huatan group，with 6 rats in each group. Except for the sham operation group，the model was established by ligating left ureter of the rats. After 3 weeks，sham operation group and model group were treated with equal amount of normal saline，the other groups were treated with the corresponding decoction，once a day. After 12 weeks，the rats were sacrificed. The serum samples were collected for determination of concentrations of BUN and Scr. The morphological changes of renal tissue were observed by HE staining. The collagen fiber was observed by Masson staining. The protein expression levels of TGF-β1，α-SMA and E-cad－herin were detected by Western blot. The mRNA expression levels of TGF-β1，Smad3，Smad7，TRB3，α-SMA and E-cadherin were detected by qRT-PCR. Results：Compared with those in sham operation group，the renal interstitial fibrosis，the con－centrations of BUN and Scr were significantly increased in the model group（P<0.01），while the collagen fiber deposition and the levels of BUN and Scr were significantly reduced by Yiqi Huayu Huatan preparation，telmisartan and Yiqi preparation（P<0.05）. Compared with those in the model group，the expressions of TGF-β1，Smad3，TRB3，and α-SMA in Yiqi Huayu Huatan，telmisartan and Yiqi group were significantly decreased（P<0.05），while the expression of E-cadherin was significantly increased（P<0.05）. There was no significant difference in the expression of Smad7 among the groups. Conclusion：Yiqi，Huayu，Huatan，Yiqi Huayu Huatan preparation and telmisartan could alleviate renal interstitial fibrosis，but Yiqi Huayu Huatan preparation，telmisartan and Yiqi prepa－ration showed better curative effect. This may be related to the inhibition of epithelial-mesenehymal transition（EMT） mediated by TRB3 and TGF-β1/Smad signal pathway.