Abstract: The nonlinear partial differential equations forthe tall piervibration of railwaybridges are derived by taking the influence of geometric nonlinearity into consideration, i.e., considering the nonlinear term caused by the direction change in axial forces and internal forces. Based on the analysis of the solution conditions ofthe equations, the vibration frequencies of a tall pierbefore and after erectingthe bridge beam, and the displacement changing pattern of the pier top are discussed. And the obtained results are compared to those by linear analysis and bythe nonlinear analysis of the forced vibration on a non-autonomous system.