Objective：To investigate the effects of ras responsive element binding protein 1（RREB1） on mesangial cell proliferation induced by transforming growth factor-β1（TGF-β1）. Methods：Mesangial cells were cultured in vitro，and transfected with TGF-β1 and RREB1-siRNA. The proliferation activity of mesangial cells were detected by CCK-8. Proliferating cell nuclear antigen（PCNA），α-smooth muscle actin（α-SMA） and RREB1 mRNA levels were detected by RT-PCR. The expression levels of PCNA，α-SMA and RREB1 proteins were detected by Western blot. Cell cycles of mesangial cells were detected by flow cytometry. Results： Compared with the control group， proliferation activity of mesangial cells in the TGF-β1 group was significantly increased（P < 0.01）. The mRNA and protein levels of PCNA，α-SMA and RREB1 levels in cells were significantly increased（P < 0.01）. The cell cycle indicated that the percentage of S phase cells increased and the percentage of G1 phase cells decreased（P < 0.01）. In RREB1-siRNA+TGF-β1 group，proliferation activity of mesangial cells was significantly decreased compared with TGF-β1 group（P < 0.01）. The expressions of PCNA，α-SMA and RREB1 levels in cells were significantly decreased（P < 0.01）. The cell cycle indicated that the percentage of S phase cells decreased and the percentage of G1 phase cells increased（P < 0.01）. Conclusion：TGF-β1 induces mesangial cells proliferation by up-regulating RREB1 expression.