The time-varying dynamic characteristics of telescopic cantilever composite laminates were studied by analytical and numerical methods. According to the classical laminate plate theory and Hamilton principle, a model of the telescopic cantilever composite laminate under in-plane excitation and lateral load was established. By choosing suitable timevarying modal functions, partial differential equations were discretized by Galerkin method. The time-varying ordinary differential linear dynamics equation is obtained. The effect of axially moving speed on dynamic characteristics of the telescopic cantilever plate is studied. The analytical solution obtained by an improved multi-scale method and numerical solution of the first-order timevarying linear system are compared.The results show that the axial speed has great influence on the dynamic characteristics of the telescopic cantilever plate. Compared with reference ［12］, the improved multi-scale method adopted in this paper is more efficient for first-order linear time-varying systems.