Aim To investigate the mechanism of action of Fuzheng Huayu recipe (FZHY) and vitamin E (Vit E) against renal interstitial fibrosis related to transforming growth factor-beta1 (TGF-β1) mediated tubular epithelial-to-mesenchymal transition. Materials and methods Renal interstitial fibrosis was induced by administration of HgCl 2 at a dose of 8 mg/kg body weight once a day for 9 weeks. Rats were randomly divided into four groups: normal, model, FZHY, and Vit E group. Rats in the latter two groups were treated with the FZHY recipe and Vit E respectively. HK-2 cells were treated with TGF-β1 for 24 h, followed by incubation with either SB-431542 (a potent and specific inhibitor of TβR-I kinase) or FZHY drug-containing serum for another 24 h. Hyp content in rat kidney tissue was assayed with Jamall's method and collagen deposition in kidney was visualized using Masson stain. Protein expression of TGF-β1, TβR-I, Smad2, p-Smad2, Smad3, and p-Smad3 was analyzed by Western blotting. Protein expression and the location of Smad3 in kidney was assayed by immunohistochemistry, E-cadherin, cytokeratin 18 (CK-18), α-SMA and TGF-β1 by immunofluorescent stain. Results FZHY and Vit E inhibited renal collagen deposition and reduced Hyp content significantly. They upregulated E-cadherin protein expression and down-regulated the protein expression of α-SMA, TGF-β1, p-Smad2, p-Smad3, and TβR-I. Lastly, they inhibited the nuclear translocation of Smad3 in fibrotic kidney tissue. FZHY drug-containing serum significantly upregulated the expression of CK-18 and down-regulated the expression of α-SMA, TβR-I, p-Smad2/3 in TGF-β1 stimulated HK-2 cells. Conclusion The mechanism of action of FZHY and Vit E against renal interstitial fibrosis is related to the reversal of tubular EMT induced by TGF-β1.