Abstract: Based on the fundamental equation and four kinds of boundary conditions of large-amplitude vibration of circular sandwich plate under uniform load, separate variables of time and space are assumed in solving for the dynamical deflection, and the stress and rotation angle in the forms of deflection function are formulated by the hypothesis of the space mode and the variational method. The control equation of time mode is also obtained by Galerkin method. Finally, the effects of initial deflection and shear parameter on the vibration characteristic are investigated.