The float glass process is widely used,since it has excellent quality and productivity,and accompanies with low cost,variable production size and convenient online process.Approximately 90%of the world production of flat glass is manufactured by float process.With the development of automotive and electronic device,the demand for high-quality and thinner flat glass is greatly increasing,which lead to an increase either in production rate or forming quality [1]Mathematical model of float process about glass forming,heat transfer in tin bath has been studied [2-4].In recent years,tin penetration in float glass and the reaction in tin bath has attracted a lot of attention [5-6].However,few studies of glass forming in tin bath were found since its complicated phenomena.In manufacturing flat glass,molten glass is poured onto the tin liquid and spread out and thinned.As a consequence of the balance between the surface tensions and gravity,the glass [7]ribbon with equilibrium thickness approximately 7 mm was produced without external process The setting of baffles and geometry of spout lip can influence the flow dynamic of molten glass and tin bath,and determine the forming of glass sheet[1,8].Optimizing geometry of the spout lip can accelerate glass smoothing.In this work,a two-dimensional model of spout lip and tin bathwas built and CFD technique was used to simulate the glass flowing phenomena in tin bath.And volume of fluid method was used to track the free surface flow of each phase.The geometry of spout lip,such as inclination angle and the distance to the tin surface,is modified to study the influence of different lip geometry on the glass flow,and also the tin bath.