The　bifurcations　of　a　composite　laminated　cantilevered　plate　are　studied,　which　is　simultaneously　forced　by　the　voltage,　base　and　in　-　plane　excitations.　The　nonlinear　partial　differential　governing　equations　of　the　system　motion　are　established　by　using　the　Hamilton＇s　principle.　The　Galerkin　approach　is　used　to　discretize　the　partial　differential　equations　to　the　ordinary　differential　equations　with　four　degree　of　freedom.　Numerical　simulations　are　also　carried　out　to　investigate　the　effects　of　the　voltage　excitation　on　the　steady-state　responses　of　the　cantilevered　piezoelectric　plate.　The　bifurcation　diagram　of　the　system　is　then　obtained.　The　system　motions　can　be　shown　as　follows:　the　chaotic　motion　to　the　multiple　periodic　motion.　The　results　show　that　the　amplitude　of　the　system　can　reduce　effectively　and　keep　the　stability　by　adjusting　the　voltage　excitation.