Abstract: Cylindrical shells are commonly used components inengineering. The buckling ofcylindrical shells under impact load is an important research topic. This paper studies the energyloss in the non-axisymmetric buckling of a cylindrical shell in threeaspects: axial buckling, circumferential buckling and axial-compressivedeformation. The results indicate that the circumferential deformation energytends to decrease with the increase of the number of edges, and takes only asmall proportion of the total deformation energy. It is concluded thatduring the process of the axial buckling, most of work done by the external force isconverted into the axial deformation energy, only a small part isconverted into the circumferential deformation energy.