Objective：This study was designed to investigate whether Kruppel-like factor 2 （KLF2） can play an important role in acute coronary syndrome（ACS）by regulating inflammatory response，providing a potential treatment for myocardial infarction in the future. Methods：The expressions of KLF2 mRNA and protein in peripheral blood mononuclear cells of ACS group（n=123）and control group（n=45）were determined by quantitative real time PCR and Western blot. Flow cytometry was used to detect the expressions of molecules on peripheral T cells of ACS group. The Gensini score of ACS patients were calculated，and the correlation between KLF2 and Gensini score in ACS patients was analyzed. Results：The expression of KLF2 protein and mRNA levels of peripheral blood mononuclear cells in ACS group were significantly lower than those in the control group. The expressions of CD62L and CCR7 on peripheral T cells in ACS group were lower than those in control group，while the expression levels of CXCR3 and CD44 were significantly higher than those in control group，and KLF2 was negatively correlated with Gensini score. Conclusion：KLF2 gene is significantly underexpressed in ACS patients，and may participate in the inflammatory response of ACS by regulating the levels of CD62L，CCR7，CXCR3 and CD44 on the surface of T cells，which may provide a new idea for the treatment of ACS.