Objective To investigate the expression of recombinant IL-37b protein and removal of the endotoxin, and identify its biological activity. Methods The prokaryotic expression vector pET28/IL-37b was constructed and to transform Escherichia coli (E.coli) Rosetta. After induction with IPTG, the recombinant protein was purified through Ni²⁺-NTA gel column and identified by SDS-PAGE and Coomassie brilliant blue staining. Then, the endotoxin protein was removed and was treated with LPS-stimulated RAW 264.7 cells. The culture supernatant was collected. The expression of IL-6 was detected by ELISA and the biological activity of the protein was identified.Results The recombinant IL-37b with high purity was expressed and the endotoxin produced by prokaryotic expression was reduced, and it was identified to have good biological activity. Conclusions In this study a recombinant IL-37b protein with high biological activity is successfully obtained.