Background Whether WW domain containing oxidoreductase (WWOX) gene is a tumor-suppressor is still controversial. Some researchers found that the transcription of the WWOX gene was lacking not only in tumor tissues but also in non-tumorous tissues and sometimes in normal tissues. Hence it is important to explore the role of the expression of the exogenous WWOX gene in the proliferation and apoptosis of primary cultured lung carcinoma cells. Methods Lipofection technique was used to determine primary cultured lung carcinoma cells containing the highly expressed exogenous WWOX gene and primary cultured cells with vectors as controls. An animal model of lung cancer was made by subcutaneous implantation of tumor cells into nude mice. RT-PCR, West blotting, flow cytometry, and TUN EL were used to detect the transcription, expression of the exogenous gene and the effect of the expression of targeted genes on the proliferation and apoptosis of the primary cultured lung carcinoma cells. Results The growth, clone formation rate (CFR) ((5.33±1.53)%) of the primary lung cancer cells transfected with the WWOX gene, tumor size and weight were significantly lower than those of the non-transfected lung cancer cells (CFR: (14.33±1.53)%) and the primary lung cancer cells transfected with blank plasmids (CFR: (11.00±1.73)%, P<0.05). The apoptosis level of primary lung cancer cells transfected with the WWOX gene ((40.72±5.20)%) was significantly higher than that of the non-transfected lung cancer cells ((2.76±0.02)%) and the primary lung cancer cells transfected with blank plasmids ((2.72±0.15)%, P<0.05). Conclusion The expression of the exogenous WWOX gene can significantly inhibit the proliferation of lung cancer cells and induce their apoptosis, suggesting that the WWOX gene possesses tumor-suppressing effect. rn