Objective: To clone the partial sequence of N+/H+ exchanger-1 (NHE-1) gene of human lung cancer cells and insert it reversely into the multiclone site of pLXSN in order to construct an antisense expression vector for tumor gene therapy in vivo. Methods: With use of the upstream and downstream primers containing Barn H I and EcoR I in their5’ ends respectively, a partial sequence of the first exon of NHE-1 gene was cloned in a length of 454 bp from genomic DNA of human lung cancer cell A549 with PCR method. The product was then directionally and reversely insert into the multiclone site of pLXSN. Finally, the constructed recombinant was identified with agarose gel electrophoresis and DNA sequencing. Results: The cloned fragment was 461 bp in length and successfully ligated to pLXSN with the identification by agarose gel electrophoresis. DNA sequencing confirmed that the fragment cloned and inserted into the vector was identical with the targeted one. Conclusion: The targeted fragment is successfully cloned and reversely inserted into pLXSN in our experiment. The antisense expression vector of NHE-1, pNHE-1. was consfructed successfully. Objective: To clone the partial sequence of N+/H+ exchanger-1 (NHE-1) gene of human lung cancer cells and insert it reversely into the multiclone site of pLXSN in order to construct an antisense expression vector for tumor gene therapy in vivo. Methods: With use of the upstream and downstream primers containing Barn HI and EcoR I in their5’ ends respectively, a partial sequence of the first exon of NHE-1 gene was cloned in a length of 454 bp from genomic DNA of human lung cancer cell Results: The cloned fragment was 461 bp in length and successfully ligated to pLXSN. With the identification by agarose gel electrophoresis. DNA sequencing confirmed that the fragment cloned and inserted into the vector was identical with the targeted one. Successfully cloned and reversely inserted into pLXSN in our experiment. The antisense expression vector of NHE-1, pNHE-1. was consfructed successfully.