The　extended　Melnikov　method,　which　was　used　to　solve　autonomous　perturbed　Hamiltonian　systems,　is　improved　to　deal　with　high-dimensional　non-autonomous　nonlinear　dynamical　systems.　The　multi-pulse　Shilnikov　type　chaotic　dynamics　of　a　parametrically　and　externally　excited,　simply　supported　rectangular　thin　plate　is　studied　by　using　the　extended　Melnikov　method.　A　two-degree-of-freedom　non-autonomous　nonlinear　system　of　the　rectangular　thin　plate　is　derived　by　the　von　Karman　type　equation　and　the　Galerkin　approach.　The　case　of　buckling　is　considered　for　the　rectangular　thin　plate.　The　extended　Melnikov　method　is　directly　applied　to　the　non-autonomous　governing　equations　of　motion　to　investigate　multi-pulse　Shilnikov　type　chaotic　motions　of　the　buckled　rectangular　thin　plate　for　the　first　time.　The　results　obtained　here　indicate　that　multi-pulse　chaotic　motions　can　occur　in　the　parametrically　and　externally　excited,　simply　supported　buckled　rectangular　thin　plate.　(C)　2009　Elsevier　Ltd.　All　rights　reserved.