For the fluid-solid interaction problem between an elastic thin cylindrical shell and a transversal cross-flow,United Lagrangian-Eulerian method is applied to build the theoretical equations for the medium deflection problem,and the deformation and surface pressure coefficient of the shell are focused on.The results suggest that,under the action of a transversal cross-flow,the round section of the shell is changed into approximate ellipse; besides,the deformation of the shell influences the surface pressure coefficient of the shell.By examples,the effects of parameters concerned on deformation and surface pressure coefficient of the shell are discussed.Finally,numerical simulation for the problem proceeds using ANSYS,and the theoretical solution confidence are consequently verified.