OBJECTIVE To study the effects of ginsenoside Rb 1（G-Rb1）on epithelial-mesenchymal transition （EMT）of renal tubular epithelial cells and its potential mechanism. METHODS The growth factor β1（TGF-β1）10 ng/mL was used to induce EMT of human renal tubular epithelial cells HK- 2. The morphological changes of HK- 2 cells were observed after treated with 10， 20，30 μmol/L G-Rb1 for 48 h. The transcriptional activities of biovector SBE in human embryonic kidney cell HEK 293 were determined after 24 h treatment with 1.0，2.5，5.0，10，20，30 μmol/L G-Rb1. Effects of above concentration of G-Rb 1 on the viability of HK- 2 cells were determined after 24 h of treatment. mRNA expressions of α-smooth muscle actin （α-SMA），collagen Ⅰ （COL-Ⅰ）and fibronectin （FN）in HK- 2 cells were detected after treated with 10，20，30 μmol/L G-Rb1 for 24 h. The expressions of α-SMA，Smad3，p-Smad3，COL-Ⅰ，FN and E-cadherin were detected after treated with 10，20，30 μmol/L G-Rb1 for 24 h. RESULTS G-Rb1 of 10-30 μmol/L significantly inhibited TGF-β1-induced EMT in HK- 2 cells and the increase of transcriptional activities of biovector SBE induced by TGF-β1（P＜0.05），but had no effects on relative activities of HK- 2 cells（P＞0.05）. The protein and mRNA expressions of α-SMA，COL-Ⅰ and FN ， the protein expressions of Smad 3 and p-Smad 3 were significantly up-regulated induced by TGF-β1（P＜0.05），while the protein expression of E-cadherin was significantly down- regulated（P＜0.05）；G-Rb1 could effectively reverse aboveprotein or mRNA expressions. CONCLUSIONS G-Rb1 can protect renal tubular epithelial cells from EMT induced byxiezhishen TGF-β1 to a certain extent ，which may be related to inhibiting the activation of TGF-β1/Smad3 signaling pathway.