Abstract: A composite circular cylindrical shell made from different materials is investigated. Based on Donnell’s shallow shell theory and classical laminated shell theory, nonlinear vibrating equation is derived, in which the effects of dynamic Young’s modulus and geometric large-amplitude are considered. Galerkin method is used to disperse the vibrating equation. The nonlinear vibrating responses of the system with the participation of two neighboring axial modes are solved by applying the multidimensional L-P method. And complex frequency-response curves indicating internal resonance are obtained, showing that the energy is transferred between the two modes which affect each other, and there is 1:1 internal resonance phenomenon in the system. Result of multiple scales method is compared with that of multidimensional L-P method, and the same conclusion is drawn.