Nonlinear　forced　vibrations　and　natural　frequency　of　sandwich　functionally　graded　material　doubly　curved　shallow　shell　with　a　rectangular　base　are　investigated.　The　sandwich　functionally　graded　material　(FGM)　doubly　curved　shell　is　subjected　to　a　harmonic　point　load　at　centre.　The　sandwich　doubly　curved　shell　with　homogeneous　face　sheets　and　FGM　face　sheets　is　considered　respectively　when　the　natural　frequencies　are　studied.　Reddy＇s　third　order　shear　deformation　theory　is　expanded　in　which　stretching　effects　in　thickness　are　considered　by　introducing　the　secant　function.　Hamilton＇s　principle　and　von-Karman　type　nonlinear　geometric　equation　are　applied　to　obtain　partial　differential　equation　of　the　FGM　sandwich　doubly　curved　shell.　Comparative　studies　with　other　shear　deformation　theories　are　carried　out　to　validate　the　present　formulation.　Navier　method　is　used　to　discuss　the　natural　vibration　frequencies　of　the　FGM　sandwich　doubly　curved　shell.　Numerical　simulation　is　applied　to　demonstrate　the　nonlinear　dynamic　responses　of　the　FGM　sandwich　doubly　curved　shell.　Multiple　periods,　quasi-period　and　chaos　are　detected　for　the　dynamic　system　for　different　core　thickness.