Objective To construct the retroviral recombinant plasmid vector encoding TK gene of the herpes simplex virus.Methods\ The specific primers were designed and synthesized to amplify the DNA fragment (PCR method) of HSV1 tk gene from the plasmid pHSV106. The length of the fragment was 1168bp.After digested by appropriate restriction endoenzymes(BamHI and EcoRI),the fragment of HSV1 tk gene was cloned into pLXSN according to its special orientation.Then the recombinant plasmid was identified by digesting of endoenzymes,PCR and DNA sequencing.Results\ The fragments digested by endoenzymes and amplified by PCR method were as large as the predicted results.DNA sequencing was the same with the sequence reported on the literature.Conclusion\ The retroviral recombinant plasmid pLXSN TK was successfully constructed.