Abstract: A model of coupling of mould vibration and molten metal flow is established,and the modified transfer matrix is used to solve this model.With the programming by use of MATLAB,the vibration magnitude and the molten metal flow pattern at different moments are obtained.The numerical simulating results show that the coupling between the mould vibration and molten metal flow indeed exists,and it influences the vibration characteristics of the maximum amplitude and the resonance speed when the mould rotates with filling molten metal.Unevenness of the wall thickness of the casting furnace tube occurs because of the mould vibration.The unevenness of the wall thickness becomes more severe with the increasing of mould eccentricity and the mass of molten metal filled.