Abstract: Objective To study Snail expression in epithelial-to-myofibroblast transition(EMT)of MGC-803 cells induced by TGF-β1.Methods MGC-803 cells were cultured in vitro.We observed cell morphological changes of MGC-803 cells at different times(0h,3h,6h,24h,48h,72h)after exposed to TGF-β1 from inverted microscope.Western blot method was employed to detect Snail,E-cadherin and Vimentin protein expressions.The transwell assay was used to observe the cell invasive ability.Result After being exposed to TGF-β1 for different times,the morphology of MGC-803 cells was changed,and pseudopodia of different levels was increased.2.Snail expression was increased from 0h to 6h(the highest at 6h).E-cadherin expression was gradually increased from 0h to 6h(the highest at 6h).Vimentin expression was also gradually increased (the lowest at 6h and the highest at 72h).Conclusion Snail proteins play an important role in the process of TGF-β1 induced EMT in MGC-803 cells,which may induce vimentin protein transcriptional expression.