Objective To express and purify the secreted protein PknG of Mycobacterium tuberculosis through prokaryotic expression system and further investigate its role in the inflammatory immune response. Methods The whole genome sequence of Mycobacterium tuberculosis PknG was obtained from the NCBI database. After the PknG was amplified by high fidelity PCR and the PknG ⁃ pET28a plasmid was constructed，the PknG protein expression was induced by IPTG，the PknG protein was purified by nickel columns and imidazole at differ⁃ ent concentrations and finally the expression of PknG protein was verified by SDS⁃PAGE and western blot. After the macrophages were treated with LPS at 0 h，12 h and 24 h，the expression of pro ⁃inflammatory cytokines TNF ⁃ α and IL⁃6 was detected by Real⁃time PCR and ELISA. Results PknG protein was successfully induced and puri⁃ fied. PknG inhibited the expression of pro⁃inflammatory cytokines TNF⁃α and IL⁃6 in LPS⁃induced macrophages. Conclusion PknG of Mycobacterium tuberculosiscan inhibit the expression of pro⁃inflammatory cytokines TNF⁃ α and IL⁃6 in macrophages. Therefore，it may be related to the potential target for the treatment of Mycobacterium tuberculosis infection in the course of sepsis.