Background: MicroRNA-647 (miR-647) has been reported to repress cell tumorigenic phenotype, while the function of miR-647 in non-small cell lung cancer was obscure. Methods: The effect of miR-647 and TRAF2 on A549 and H1299 cells was explored through Methyl thiazolyl tetrazolium (MTT) assay, colony formation and cell cycle assays. Luciferase reporter assays, reverse transcription quantitative PCR (RT-qPCR) and Western blot assay were carried out to determine that TRAF2 is directly regulated by miR-647. The effect of miR-647/ TRAF2 axis on p65 protein level in nucleus or total was detected by Western blot assay. Results: Here, we found that miR-647 was high expression in tumor that under argon-helium cryoablation treatment in contrast to the tumor under non argon-helium cryoablation treatment and inhibited cell proliferation of A549 and H1299 cells by inducing G1-S transition. TRAF2 was confirmed as a target of miR-647. TRAF2 overexpression partially rescued the suppressive function of miR-647 in A549 and H1299 cells. Moreover, we found that miR-647 repressed lung carcinogenesis by attenuating NF-κB pathway. Conclusion: In all, our study demonstrates that miR-647 functions as tumor suppressor via targeting and down-regulating the expression of TRAF2 and NF-κB signaling pathway in non-small cell lung cancer. [ABSTRACT FROM AUTHOR]