Abstract: Objective To explore the role of SIRT1 in the occurrence of epithelial-mesenchymal transition (EMT) in EC-9706 and Eca-109 cells and the possible mechanism. Methods Three chemically synthesized siRNA targeting SIRT1 were transfected into EC-9706 and Eca-109 cells with the non-transfected cells and cells transfected with the negative siRNAs as controls. Real-time PCR and Western blotting were used to detect the expressions of SIRT1, E-cadherin, vimentin, Snail, Twist1 and ZEB in the cells. Transwell invasion assay and wounding healing assay were used to examine the changes in the invasion and metastasis abilities of the cells after transfection. Results EC-9706 and Eca-109 cells transfected with SIRT1 siRNA1 and SIRT1 siRNA3 showed significantly decreased mRNA and protein expressions of SIRT1 (P<0.05). Transwell invasion assay and wounding healing assay showed that transfection with SIRT1 siRNA1 and SIRT1 siRNA3 caused significantly lowered invasion and metastasis abilities in EC-9706 and Eca-109 cells (P<0.05). In EC-9706 and Eca-109 cells transfected with SIRT1 siRNA1 and SIRT1 siRNA3, the expression level of E-cadherin was significantly increased while the expressions of vimentin, Snail and Twist were significantly lowered (P<0.05). Conclusion SIRT1 participates in the invasion and metastasis of EC-9706 and Eca- 109 cells probably by inducing EMT via regulating the expression of Snail.