In order to study the effect of NAG7 gene on NAG7 down-regulated nasopharyngeal carcinoma (NPC) cell line HNE1, the pcDNA3.1(+)/NAG7 mammalian expression recombination was constructed and transfected into HNE1 cells. G418 was used to obtain the neomycin-resistant transformants of which indicated the vector was present in the HNE1 cells. The expression of NAG7 gene was detected by RT-PCR and Northern blot. The cytobiologic characteriztions of the transfected HNE1 cells were probed by population double time (PDT), xenograft of nude mice and cell cycle analysis. The results showed that the PDT of G418-resistant HNE1 cells with expression of NAG7 was longer than that of vector transfected HNE1 cells and untranstected HNE1 cells, and the more NAG7 transfected cells went into phase G0-G1 compared with the two other cells. It also presented inhibited the tumor formation in mude mice. Thus, these data suggested that NAG7 gene play an important role in the cell growth of HNE1, and might be a good candidate of tumor suppressor gene correlated with NPC.