Objective To study the effect and molecular mechanism of epigallocaechin-3-gallate (EGCG) on epithelial-mesenchymal transition (EMT) in vitro induced by human recombinant TGF-β1 protein in squamous cell carcinoma of the head and neck.Methods EMT morphological changes of Tu686 cells were observed after sequential treatment of 5 ng/ml TGF-β1 and 20 μmol/L EGCG.Tu686 cells were collected after the treatment of 5 ng/ml TGF-β1 for 24 h and EGCG with different concentrations (0,10,20,30 μmol/L) for another 24 h or 20 μmol/L EGCG treatment for different time phase(6,12,24 h).Then RT-PCR and Western-blot were applied to detect mRNA and protien expression level of epithelial cell marker E-cadherin,mesenchymal cell marker Vimentin and Smad7,an inhibit molecule of TGF-β1 mediated pathway in Tu686 cells.Results TGF-β1 successfully induced characterized EMT morphological and molecular changes in Tu686 cells,in which expression of E-cadherin decreased,Vimentin increased and Smad7 declined.However,EGCG could reverse the TGF-β1 mediated process of EMT by downregulating the expression of Vimentin and upregulating the expression of E-cadherin and Smad7.Conclusion EGCG significantly inhibits TGF-β1-mediated EMT inTu686 cell lines of SCCHN,which maybe associated with the upregulated-expression of Smad7,an inhibitor in TGF-β1 signaling pathway.