BACKGROUND The human FHIT gene at chromosome 3p14.2 is a tumor suppressor gene, and its abnormality in structure and function is related to carcinogenesis and progression of lung cancer. It is postulated that FHIT and NIT1 likewise collaborate in biochemical or cellular pathway in mammalian cells, but their molecular mechanisms in lung cancer cell are still unknown. The aim of this study is to construct procaryotic expression vector of human NIT1, providing a foundation to explore the expression of human NIT1 protein and to study the interaction of NIT1 and FHIT genes in lung cancer cell lines. METHODS The NIT1 cDNA was acquired by RT-PCR. EcoRI/NotI digested PCR product was directly cloned into procaryotic expression vector pET-32a. RESULTS The sequence of NIT1 cDNA clone exactly corresponded with the sequence of NIT1 cDNA in GenBank. The expectant fragments of DNA were obtained after recombinant procaryotic expression vector was digested by EcoRI and NotI. CONCLUSIONS The procaryotic expression vector of human NIT1 is successfully constructed by RT-PCR and direct clone. It provides an important basis to detect the expression of NIT1 protein and to further explore the relationship between NIT1 and FHIT genes in oncogenesis and development of human lung cancer.