Abstract: Objective: To analyze the association of abnormal methylation of CpG islands in the promoter domain of multiple tumor suppressor genes with non-small cell lung cancer. Methods:Methylation specific PCR was used to detect methylation of tumor suppressor genes (TSG) and the data were analyzed by logistic regression analysis. Results: The methylation data of 94lung cancer cases were used in this study. The analysis revealed promoter domain methylation in more than one TSG in 91.49% of lung cancer tissue samples (P<0.01). Frequencies of promoter methylation in P 16INK 4a, DAPK, MGMT, TIMP-3 and RARß in lung cancer tissue were 41.49%,50.00%,17.02%,24.47% and 68.09%, respectively, with a significant difference from those in normal lung tissue. The effect of TSG promoter methylation on squamous cell can-cer, central lung cancer, and stage Ⅲor more was increased as the methylation index (MI) increased. Smoking increased the risk of p 16INK 4a and DAPK methylation by OR of 21.714 and 15.268 (P<0.01), respectively. There was a dose-re -sponse relationship between smoking history and methylation of TSG. Conclusion:Smoking is an important risk factor for methylation of TSG and the methylation of multiple TSG plays a key role in the pathogenesis of lung cancer.