The　dynamic　responses　of　two　kinds　of　simple-supported　beams　with　single　layer　and　double-layer　under　a　moving　load　were　analyzed　based　on　the　theory　of　nonlinear　dynamics.　The　equations　of　motion　are　derived　by　using　Hamilton＇s　principle　and　von　Karman　type　equations　for　the　two　models.　Galerkin＇s　method　was　employed　to　obtain　the　ordinary　differential　equations　of　motion.　First　we　obtain　the　periodic　motion　waveforms　in　the　mid-point　of　the　beams　at　the　same　initial　velocity,　and　the　result　show　that　the　amplitude　of　the　double-layer　model　is　much　smaller　then　that　of　the　single-layer　model.　Then　for　the　two　models,　the　vibration　response　and　critical　velocity　were　studied　considering　the　effect　of　the　structural　parameters,　the　magnitude　and　velocity　of　moving　load.　The　results　of　numerical　simulation　show　that　double-layer　beam　model　has　better　vibration　suppression　performance　than　single-layer　beam　model.