Aim To investigate the effects of different level testosterone on production of monocyte chemoattractant protein-1(MCP-1) in HUVEC and possible mechanism,so as to study the relationship between atherosclerosis and testosterone. Method After foreclosed HUVEC with LPS and different testosterone(control,3×10-10 mol/L,physiological concentration 3×10-9 and 3×10 -8 mol/L,3×10-6,3×10-5 mol/L),protein production of MCP-1 was examined by ELISA and mRNA level by RT-PCR.To study the mechanism,we added Fluramide or Aminoglutethimide beforehand in the medium for 5 hours and reduplicated above experimental processes. Results In contrast to control,protein production of lower testosterone was significantly increased and this effect was contracted by fluramide;while protein production were significantly decreased by 3×10-5 mol/L testosterone and mRNA level decreased by 3×10-9,3×10-6,3×10-5 mol/L testosterone,those effects were weakened by aminoglutethimide.Conclusion Lower testosterone may stimulate inflammation of HUVEC;testosterone of physiological level or above could suppress HUVEC from inflammation and dysfunction by converting to estradiol.