Objective To investigate the effect of RAS Responsive Element Binding Protein 1(RREB1) on mesangial cell proliferation induced by transforming growth factor-β（TGF-β1）. Methods Mesangial cells were cultured in vitro,TGF-β1 and RREB1-siRNA were transfected. 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.And cell cycles were detected by flow cytometry. Results Compared with the control group, the TGF-β1 group showed that proliferation activity of mesangial cells were 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). Conclusions TGF-β1 induced mesangial cells proliferation by up regulating RREB1.