Abstract: The finite element analysis（FEA） based on fluid-structure interaction（FSI） is applied in simulating the three-dimensional water hammer in the pipe.The FSI is achieved through the Arbitrary Lagrangian Eulerian（ALE） method.The results of finite element model are consistent with that of one-dimensional classical model.The model and method used in this research are confirmed.The maximum breathing deformation and the dynamic stresses in pipe wall are created at a significant time after the wave front has passed.The maximum deformation does not occur at either the wave front,or near the fixed ends of the pipe,but occurs about one-third of a pipe diameter away from the end.Among the dynamic stresses in pipe wall,the hoop stress is dominant in the effective stress and has the same period with water pressure wave.Finally,the simulation and analysis carried in this paper show the correctness and the affectivity of the proposed method.