A modified mixed variational principle in cylindrical coordinate system for elastic cylindrical panels with damping is established, and the state-vector formulation with damping parameters is derived from the variational principle. Based on the precise integration method and Muller method, a new solution for the effect of damping on the natural frequency, harmonic vibration and complex frequency response of simply supported laminated plates/shells is presented. The results of the numerical examples show that the current approach offers good predictive capability. The variational principle presented in the paper will be of benefit to the derivation of the semi-analytical solution for the dynamic problems of the laminated structures with damping and complicated boundary conditions.