Objective To construct anti-astrocyte elevated gene-1(AEG-1)single-chain variable antibody (V23)prokaryotic ex-pression vector,and to conduct the protein purification and immunological activity detection.Methods The Primer5 software was applied to design the primers aiming at the gene sequence of the antibody anti-AEG-1 single-chain variable region for constructing the prokaryotic expression plasmid of PRsetC/V23.After the enzyme digestion by the restriction enzyme Pst1 and correct DNA se-quencing,the prokaryotic expression plasmid was led to E.coli BL21 ,the prokaryotic expression engineering strain containing the V23 gene was constructed.After the induction with IPTG,the interest protein was purified by the magnetic beads with the HIS tag,and the content of interest protein was determined by the SDS-PAGE electrophoresis.Western blot and ELISA were adopted to detect the immune activity of the nti-AEG-1 single-chain variable region antibody.Results For the constructed prokaryotic expres-sion plasmid PRsetC/V23,the single enzyme digestion and sequencing analysis displayed that the constructed V23 gene was com-pletely consistent to the designing sequences.After IPTG induction,SDS-PAGE electrophoresis showed an apparent protein band at 31×103 ,the Western blot detection showed a specific AEG-1 response band at 80 ×103 ,the ELISA test showed the positive re-sults.Conclusion The PRsetC/V23 prokaryotic expression plasmid and the V23 prokaryotic expression engineering strain are suc-cessfully constructed,this engineering strain can express anti-AEG-1 single-chain variable region antibody protein,and the protein has good immune activity.