Objective To investigate the expression of PinX1 gene and its functional effects in human nasopharyngeal carcinoma (NPC) cells. Methods Expression vectors of human PinX1 (pEGFPC3PinX1) and its small interfering RNA (PinX1FAMsiRNA) were constructed and transfected into NPC 58F cells by lipofectamine TM 2000. First, mRNA level of PinX1 was examined with RTPCR. And then, its effects on mRNA level of telomerase catalytic subunit (hTERT), telomerase activity, cell proliferation and apoptosis were examined using semiquantitative RTPCR, stretch PCR, MTT assay and flow cytometry, respectively. Results The analysis of restriction and sequencing showed that the recombining plasmids were successfully constructed. The results also showed that transfection of pEGFPC3PinX1 and PinX1FAMsiRNA into NPC 58F cells increased PinX1 mRNA by 1.6fold and reduced PinX1 mRNA by 70%, respectively. Overexpression of PinX1 decreased hTERT mRNA by 29.9% (P<0.05), significantly reduced telomerase activity (P<0.05), inhibited cell growth, increased cell apoptotic index from 19.27%±0.76% to 49.73%±2.70%(P<0.05). The study further showed that silencing PinX1 did not alter all the characteristics of NPC 5-8F cells, including cell growth, mRNA level of hTERT, telomerase activity and cell apoptotic index (P>0.05). Conclusion Transfection of pEGFPC3PinX1 into NPC 58F cells can inhibit the expression of human telomerase activity and hTERT, decrease cell growth and induce apoptosis. Besides, inhibitory functions can’t work by silencing PinX1 with PinX1FAMsiRNA. Taking together, PinX1 as an endogenous telomerase inhibitor has application potential to tumortargeted gene therapy.