Three-dimensional analytical solution of simply supported laminated thick rectangular plates on the Winkler foundation was derived by the finite integral transform method and state space theory.During the analysis process,the preselection of various stress and displacement functions used commonly in thick plate model was abandoned,and based on the basic elasticity equations and variable substitution,a system of partial differential equations with respect to stress and displacement components was reduced to two matrix differential equations,one was second order and another was fourth order.The transfer equation of laminated plates was derived according to the continuity of state space vector of joint surface,the three-dimensional analytical solution of simply supported laminated thick rectangular plates on the Winkler foundation were obtained by the finite integral inverse transform method.Numerical results demonstrate the validity of the method in this paper,and compared with other methods,this method can greatly improve the solution efficiency because of the technique of reduced order.