An　analysis　on　the　nonlinear　vibrations　of　a　simply-supported　composite　laminated　rectangular　plate　with　both　parametrical　and　forcing　excitations　was　presented.　Based　on　the　Reddy＇s　high-order　shear　deformation　theory　and　the　model　of　the　von　Karman　type　geometric　nonlinearity,　nonlinear　governing　partial　differential　equations　of　motion　were　derived　by　using　the　Hamilton　principle.　The　linear　external　damping　was　supposde　to　existion　the　plate.　Then,　useing　the　second-order　Galerkin　discretization　approach,　the　partial　differential　governing　equations　of　motion　were　transformed　to　nonlinear　ordinary　differential　equations　under　parametrical　and　forcing　excitations,　which　leads　to　the　periodic　and　chaotic　oscillations.　The　method　of　multiple　scales　was　used　to　get　four　averaged　equations.　From　the　averaged　equations　obtained　here,　the　theory　of　normal　form　was　used　to　give　the　explicit　expressions　of　normal　form,　based　on　which,　high-dimensional　Melnikov　method　was　utilized　to　analyze　the　global　bifurcations　and　chaotic　motions　of　composite　laminated　rectangular　thin　plates.　The　results　obtained　above　illustrate　the　existence　of　chaos　in　the　Smale　horseshoe　sense　in　parametrically　excited　and　forcing　excited　composite　laminated　plates.　The　chaotic　motions　of　composite　laminated　plates　were　also　found　by　using　numerical　simulation.　The　simulation　results　indicate　that　there　exist　different　shapes　of　chaotic　responses　in　the　nonlinear　oscillations　of　composite　laminated　plate　under　certain　force　excitations,　parametric　excitations　and　initial　conditions.