An　algorithm　integrating　reduced　order　model　(ROM),　equivalent　linearization　(EL),　and　finite　element　method　(FEM)　is　proposed　to　carry　out　geometrically　nonlinear　random　vibration　analysis　of　stiffened　plates　under　acoustic　pressure　loading.　Based　on　large　deflection　finite　element　formulation,　the　nonlinear　equations　of　motion　of　stiffened　plates　are　obtained.　To　reduce　the　computation,　a　reduced　order　model　of　the　structures　is　established.　Then　the　EL　technique　is　incorporated　into　FE　software　NASTRAN　by　the　direct　matrix　abstraction　program　(DMAP).　For　the　stiffened　plates,　a　finite　element　model　of　beam　and　plate　assembly　is　established,　in　which　the　nodes　of　beam　elements　are　shared　with　shell　elements,　and　the　offset　and　section　properties　of　the　beam　are　set.　The　presented　method　can　capture　the　root-mean-square　(RMS)　of　the　stress　responses　of　shell　and　beam　elements　of　stiffened　plates,　and　analyze　the　stress　distribution　of　the　stiffened　surface　and　the　unstiffened　surface,　respectively.　Finally,　the　statistical　dynamic　response　results　obtained　by　linear　and　EL　methods　are　compared.　It　is　shown　that　the　proposed　method　can　be　used　to　analyze　the　geometrically　nonlinear　random　responses　of　stiffened　plates.　The　geometric　nonlinearity　plays　an　important　role　in　the　vibration　response　of　stiffened　plates,　particularly　at　high　acoustic　pressure　loading.　©　2020,　Editorial　Department　of　Transactions　of　NUAA.　All　right　reserved.