Objective To explore the role of Galectin3 in transforming growth factor-β(TGF-β)-induced epithelial-mesenchymal transition (EMT) in A549 cells. Methods Galectin3 was over-expressed in an A549 cell line. EMT was induced in lung cancer A549 cells by adding TGF-β. The expressions of Galectin3,E-cadherin,and vimentin were determined by Western blot. The protein expression of E-cadherin and the morphological changes of the cells were detected by immunofluorescence. Cellular proliferation was analyzed with cell counting kit-8,and the cellular migration and invasion was measured by scratches healing and Transwell assay,respectively.Results When only Galectin3 was over-expressed in A549 cell line,the expression levels of EMT-related proteins such as E-cadherin and vimentin were not changed,and the abilities of cellular proliferation,invasion,and migration were not changed either. When the EMT was induced by TGF-β in A549 cells,the E-cadherin expression was down-regulated and the vimentin expression was up-regulated in A549 cells with Galectin3 over-expression. There was no significant change in cellular proliferation,whereas the abilities of cellular invasion and migration were enhanced.Conclusion The TGF-β-induced EMT in A549 cells can be enhanced by Galectin3.