Lung cancer is one of the most lethal cancers in China because of its high incidence and highmortality. Omithine decarboxylase (ODC), an important enzyme in polyamine biosynthesis, is increased in pression show inhibitory effects on cancer cell growth, so ODC can be useful in gene diagnosis and gene therapy of cancers. In this study, we ODC on lung cancer cells. A-549 cells were infected with rAd-ODC/Ex3as,a recombinant adenovirus containing the cytomegalovirus promoter, green fluorescent protein gene and 120 e mouse xenograft model was used in the tumorigenicity test. Reverse transcription-polymerase chain reaction, Weste blot and immunoo study the expressions of ODC on lung cancers. It was found that the growth of cells infected with rAd-ODC/Ex3as was substantially inhibited and cells were arrested at G1 phase. Cells raft model. The expression of ODC mRNA and ODC protein levels in lung cancer tissues was significantly higher than that es (P＜0.05), which correlated significantly with the stage of lung cancer (P＜0.05). This study suggested that rAd-ODC/Ex3as has antitumor activity in human lung cancer cells. The ODC gene might play an important role in lung cancer and the overexpression of ODC might be related to the occurrence and development of lung cancer.