Abstract: The elastic buckling problem of large-scale composite sandwich tubes in a satellite structure is analyzed. The geometry equations, constitutive equations and strain energy expressions of cylinder shell, conical shell and frames are constructed separately. And the potential energy of external forces is obtained under given loading conditions. According to the boundary conditions, the trigonometric series are applied to describing the displacement field. The principle of minimum potential energy is used to determine the critical load. The critical loads are obtained considering or neglecting the effects of sandwich shear deformation and shell taper angle separately, and then they are compared between the two conditions, demonstrating that the maximum error is less than 10%. Based on this research, a simplified method can be applied in the design stage of the large-scale composite sandwich tube in engineering.