The　homoclinic　phenomena　in　double-layered　nanoplates　(DLNP)　are　investigated.　Based　on　the　nonlocal　continuum　theory,　the　nonlinear　dynamical　equations　for　DLNP　subjected　to　in-plane　excitation　are　derived　by　double-mode　Galerkin　truncation.　The　extended　Melnikov　method　is　utilized　to　discuss　the　homoclinic　phenomena　and　chaotic　motion　for　the　buckled　DLNP　system.　The　criterions　for　the　existence　of　transverse　homoclinic　orbits　are　established　under　different　four　buckling　cases　(i.e.,　the　first-　and　second-type　synchronous　buckling　as　well　as　asynchronous　buckling).　And　the　results　derived　by　the　above-mentioned　analysis　are　verified　by　molecular　dynamics　and　Lyapunov　exponent　spectrum.　Small-scale　effect　on　the　homoclinic　motion　is　mainly　inspected.　From　the　result,　it　is　rather　novel　that　the　transversality　condition　is　independent　of　the　nonlinear　terms　in　the　equations.　This　fact　means　that　it　is　not　necessary　to　distinguish　whether　the　boundaries　are　movable　or　immovable　for　the　in-plane　parametric　excitation　DLNP.　The　parametric　regime　where　homoclinic　phenomena　appear　shrinks　with　the　augment　of　nonlocal　parameter　for　the　first-type　synchronous　buckling　case.　However,　this　trend　is　just　opposite　for　the　other　three　buckling　cases.　Finally,　it　can　be　seen　that　homoclinic　phenomena　more　likely　occur　on　Mode　I　(i.e.,　lower　mode)　for　the　second-type　synchronous　and　asynchronous　buckling　cases.　However,　the　homoclinic　motion　for　the　first-type　asynchronous　buckling　most　likely　takes　place　on　Mode　III.