This　paper　presents　an　analysis　on　the　nonlinear　vibrations　of　a　simply　supported　composite　laminated　rectangular　thin　plate　with　parametric　and　forcing　excitations.　In　accordance　with　the　Reddy＇s　high-order　shear　deformation　theory　and　the　model　of　von　Karman　type　geometric　nonlinearity,　the　nonlinear　governing　partial　differential　equations　of　motion　can　be　derived　by　the　using　the　Hamiltonian　principle.　The　Galerkin　discretization　approach　and　the　method　of　multiple　scales　are　then　incorporated　to　formulate　the　four-dimensional　averaged　equation.　The　case　of　1:1　internal　resonance　as　well　as　fundamental　parametric　resonance　for　the　simply　supported　composite　laminated　rectangular　thin　plate　is　studied　by　numerical　simulation.　The　results　of　numerical　simulation　demonstrate　that　periodic　and　chaotic　motions　exist　in　the　composite　laminated　rectangular　thin　plate　under　certain　excitation　conditions.