This　paper　is　devoted　to　investigate　the　nonlinear　dynamics,　bifurcation　and　chaos　of　the　piezoelectric　composite　lattice　sandwich　plate　with　1:3　internal　resonance.　Galerkin　method　is　used　to　discretize　the　nonlinear　partial　differential　governing　equations　of　motion　into　the　ordinary　differential　equations.　The　multi-scale　method　is　used　to　obtain　the　modulation　equations　of　the　piezoelectric　composite　lattice　sandwich　plate　in　the　polar　coordinates　and　Cartesian　coordinates　in　the　primary　and　parametric　resonances,　respectively.　Using　NewtonRaphson　method,　the　bifurcation　diagrams　of　the　steady-state　equilibrium　solution　are　obtained　for　the　modulation　equation　with　the　change　of　the　system　parameters.　The　stability　of　the　steady-state　equilibrium　solution　is　analyzed　for　the　modulation　equation.　The　existence　of　the　static　bifurcations,　such　as　the　saddle-node　bifurcation,　pitchfork　bifurcation　and　Hopf　dynamic　bifurcations　are　found.　The　complex　nonlinear　jump　phenomena　caused　by　the　existence　of　the　multiple　nonlinear　steady-state　solution　regions　are　analyzed　in　detail.　Fourthorder　Runge-Kutta　method　is　used　to　continue　tracing　the　nonlinear　periodic　solution　of　the　modulation　equation　in　Cartesian　coordinates.　The　time-history　diagram,　phase　portrait　and　Poincare　map　are　obtained　for　the　piezoelectric　composite　lattice　sandwich　plate　in　the　nonlinear　resonance.　The　dynamic　process　of　the　nonlinear　periodic　solution　is　described　for　the　modulation　equation　from　the　limit　cycle　oscillation　to　the　chaotic　attractor　in　detail.