Objective To study the roles of protein kinase C (PKC) in the signal transduction pathway of LPS induced nuclear transcription factor (NF) κB activation of alveolar macrophages(AMs). Methods NF κB level in nuclear protein extraction of AMs was detected by sandwich ELISA. Intranuclear translocation of NF κB was observed by immunocytochemical staining. Results LPS could induce NF κB activation of AMs in time and dose dependent manners. Immunohistochemical staining revealed intranuclear translocation following LPS induction. Specific calphostin C (Cal C) and pyrrolidine dithiocarbamate (PDTC) could inhibit LPS induced NF κB activation. Conclusion PKC, as a up stream messenger, is involved in the signal transduction pathway of LPS induced NF κB activation.