Nicotine can significantly down-regulate the expressional level of E-cadherin mRNA and protein of A549 cells in a manner of dose and time-dependent (P < 0.01, P < 0.01); Nicotine can significantly up-regulate the expressional level of Vimentin mRNA and protein of A549 cells in a manner of dose and time-dependent (P < 0.01, P < 0.01); Immunofluorescence results showed that β-catenin protein was significantly transfered to nucleus; Scratch test and Transwell assay showed that Nicotine could remarkably increase the migration and invasion potential of lung cancer cells (P < 0.01, P < 0.01). The gene discussed is CDH1; the disease is lung cancer.