This　paper　investigates　the　multi-pulse　global　heteroclinic　bifurcations　and　chaotic　dynamics　for　the　nonlinear　vibrations　of　a　simply　supported　rectangular　thin　plate　by　using　an　extended　Melnikov　method　in　the　resonant　case.　The　rectangular　thin　plate　is　subjected　to　spatially　and　temporally　varying　transversal　and　in-plane　excitations,　simultaneously.　The　equations　of　motion　for　the　rectangular　thin　plate　are　derived　from　the　von　Kármán　equation.　Applying　the　method　of　multiple　scales　and　Galerkin’s　approach　to　the　partial　differential　governing　equation,　the　four-dimensional　averaged　equation　is　obtained　for　the　case　of　1:2　internal　resonance　and　primary　parametric　resonance.　From　the　averaged　equations　obtained,　the　theory　of　normal　form　is　used　to　derive　the　explicit　expressions　of　normal　form　with　a　double　zero　and　a　pair　of　pure　imaginary　Eigenvalues.　Based　on　the　explicit　expressions　of　normal　form,　the　extended　Melnikov　method　is　used　to　analyze　the　multi-pulse　heteroclinic　bifurcations　and　chaotic　dynamics　of　the　rectangular　thin　plate.　The　contribution　of　the　paper　is　the　simplification　of　the　extended　Melnikov　method.　The　extended　Melnikov　function　can　be　simplified　in　the　resonant　case　and　does　not　depend　on　the　perturbation　parameter.　The　necessary　conditions　of　the　existence　for　the　Shilnikov　type　multi-pulse　chaotic　dynamics　of　the　rectangular　thin　plate　are　analytically　obtained.　Numerical　simulations　also　display　that　the　Shilnikov　type　multi-pulse　chaotic　motions　can　occur　in　the　rectangular　thin　plate.　Overall,　both　theoretical　and　numerical　studies　demonstrate　that　the　chaos　for　the　Smale　horseshoe　sense　exists　in　the　rectangular　thin　plate.　©　2013,　The　Author(s).