Abstract: Objective:The prokaryotic expression system of the target gene plnEF was constructed,and the engineered strain BL21-pET28a-PL-plnEF was induced to express and purify the target fusion protein,so as to obtain a large amount of the higher purity Lactobacillus plantarum PlnEF bacteriocin and develop a new food preservative. Method:The recombinant plasmid containing plnEF gene was constructed and transferred into E. coli BL21.The target protein was expressed by IPTG,and the fusion protein PlnEF was purified to detect the molecular weight and antibacterial activity. Result:The recombinant plasmid pET28a-PL-plnEF was successfully expressed in E. coli BL21,and the PlnEF protein was synthesized with a molecular weight of 15.6 kDa. The fusion protein had good antibacterial activity against Escherichia coli JM109. Conclusion:The plnEF gene fragment could be correctly expressed and active in prokaryotic cells,which would lay a foundation for further research and development of the bacteriocin as a biological preservative.