Abstract: Dynamic effect of vehicle load on bridge and bank slope under pile foundation was investigated.Taking an calculating example of Lizi ditch special bridge,two three-dimensional dynamical analysis models for upper and lower departments of the bridge and for foundation-bank slope were set up respectively.The large-scale project analysis software ANSYS was adopted to analyze dynamic response of bridge with large span and tall piers and rail irregularity,and the security and stability of bank slope under pile foundation due to running train.Prestressing cables were adopled to strengthen the slope so as to ensure the stability of the bank slope.