Abstract: An axisymmetric finite element-boundary element coupled computational method is proposed for the dynamics of cylindrical shells with endplates in water . Due to the periodic characteristics of the structure， the movement of the cylindrical shell and end plate can be determined by examining their meridional movement， and the meridians are discretized into several elements for further analysis. By using the energy method， the elemental matrices are obtained and assembled into the global matrices. Then the discrete schemes for structural motion with the finite element is established. Considering the axisymmetric characteristic of the fluid， an axisymmetric boundary element on the meridians is established and the calculation format for fluid-elastic forces on the finite elements is given. The fluid forces are then converted into an equivalent nodal force at the nodes and the effects of the fluid are evaluated by the added mass， damping， and stiffness matrices. By combining the structural motion and the schemes of fluid-elastic forces， an axisymmetric finite element-boundary element coupling method is developed to solve this fluid-structure coupling problem. The calculated results presented in this paper demonstrate good agreement with existing theoretical solutions and commercial analysis software， validating the accuracy of present method. Moreover， this method exhibits higher computational efficiency compared to commercial analysis software. It allows for direct determination of the mass and stiffness matrices of cylindrical shells in fluid， facilitating fast calculation of forced vibration. Based on this method， the wet frequencies and stability characteristics of complex cylindrical shells with end plates in axial flow are analyzed. The results show that the end plates will change the flow velocities on the cylindrical shell and make it more easily to instability.