In order to explore the role of Krupperl-like factor 4(KLF4) in regulating the expression of IL-6 induced by lipopolysaccharide (LPS). mRNA and protein levels of KLF4 in various periods were determined by RT-PCR and Western blot. A full-length cDNA or antisense oligonucleotides of KLF4 was transfected into RAW264.7 macrophages. The expression and release of IL-6 were analyzed by RT-PCR and ELISA. The transcription and DNA binding activities of KLF4 to the IL-6 promoter were detected by the luciferase reporter and EMSA. The results showed that treatment of RAW264.7 macrophages with LPS resulted in increase in KLF4 and IL-6 protein levels; KLF4 overexpression decreased the expression and release of IL-6, while KLF4 inhibition increased the expression of IL-6. The results from luciferase reporter gene assay demonstrated that KLF4 could inhibit the transcriptional activity of IL-6 gene. The results from EMSA demonstrated that KLF4 could not bind to the KLF4 binding sites on the promoter of IL-6 gene. These data suggested that LPS can stimulated the expression of KLF4 and release of IL-6 in RAW264.7 macrophages; KLF4 can inhibited the release of IL-6 in LPS-stimulated RAW264.7 macrophages; KLF4 can inhibited the transcription activity of IL-6 promoter in RAW264.7 macrophages; this effect of KLF4 is not through binding the IL-6 promoter directly.