Aim To investigate the effect and mechanism of simvastatin on the expressions of inflammatory factors in cultured rat vascular smooth muscle cells （VSMC） induced by oxidized low density lipoprotein （ox-LDL）.Methods The rat VSMC were cultured in vitro.Through pretreatment with anti-TLR4 antibody and simvastatin prior to ox-LDL exposure,the expression of TLR4 mRNA was determined by reverse transcription-polymerase chain reaction （RT-PCR）.The levels of IL-6 and TNF-α in supernatant medium were detected by enzyme linked immunosorbent assay （ELISA）.Results Incubation of VSMC with ox-LDL could enhance the expressions of IL-6 and TNF-α.The expressions of IL-6 and TNF-α were attenuated by pretreatment with anti-TLR4 antibody prior to ox-LDL exposure in a concentration-dependent manner （P<0.01）.Different concentrations of simvastatin dramatically reduce the expression of TLR4 mRNA （P<0.01）,the effect was concentration-dependent,at the same time,the expressions of IL-6 and TNF-α were attenuated by simvastatin in a concentration-dependent manner （P<0.05）.Simvastatin dramatically reduced the expressions of TLR4 mRNA,IL-6 and TNF-αby pretreatment with anti-TLR4 antibody prior to ox-LDL exposure compared to the Simvastatin group（P<0.01）.Conclusions Simvastatin could reduce the expressions of inflammatory factors in VSMC induced by ox-LDL,the mechanism may be by inhibiting the activation of TLR4 signaling.