Abstract: To construct the prokaryotic expression vector pQE- 30-luxS and express the fusion protein. The luxS gene was amplified by polymerase chain reaction ( PCR) using the DNA of Lactobacillus plantarum KLDS1.0391 as template, then it was cloned to vector pMD18-T simple.After the luxS gene was identified to be correct, the target gene was connected with expression vector pQE-30 and the recombinant plasmid pQE-30-luxS was transformed into E.coli M15.The recombinant expressed proteins induced by Isopropyl β- D-1- Thiogalactopyranoside ( IPTG) were analyzed and identified with SDS-PAGE.The results showed that the prokaryotic expression vector pQE-30- luxS was successfully constructed.The sequence of cloned luxS was identical with the known sequences, and LuxS protein was successfully expressed in E.coli M15.The results referred to above underlaid the relationship between the synthesis of AI-2 in vitro and the synthesis of bacteriocins of Lactobacillus plantarum KLDS1.0391.