New　three-phase　composite　structures　reinforced　synergistically　by　nano-fillers　and　macroscopic　fibers　have　great　application　potential.　This　paper　presents　a　general　framework　for　material　properties　calculation　and　the　free　vibration　analysis　of　three-phase　composite　shell　structures.　Based　on　this　methodological　system,　the　free　vibration　characteristics　of　three　types　of　nano-enhanced　functionally　graded　three-phase　composite　cylindrical　shells　are　investigated.　First,　the　equivalent　mechanical　properties　of　these　three　three-phase　composites　were　evaluated　using　the　Halpin-Tsai　and　Mori-Tanaka　models.　The　governing　equations　for　the　cylindrical　shells　were　derived　based　on　the　first-order　shear　deformation　theory　(FSDT)　and　Hamilton＇s　principle.　The　equations　were　discretized　using　Galerkin＇s　method　and　solved　to　obtain　the　natural　frequencies　and　mode　shapes.　The　finite　element　simulation　results　and　existing　literature　verified　the　accuracy　and　reliability　of　the　method　in　this　paper.　The　synergistic　effects　of　nano-reinforced　fillers　and　macroscopic　fibers　on　the　free　vibrations　of　these　structures　were　also　analyzed.　Among　them,　the　natural　frequency　of　the　three-phase　composite　cylindrical　shells　was　the　highest　when　graphene　platelets　(GPLs)　were　used　as　the　nano-reinforced　fillers,　which　was　150.32%　higher　than　that　of　fiber-reinforced　epoxy　composite　cylindrical　shells.　These　studies　provide　theoretical　guidance　for　the　design　and　manufacture　of　such　symmetric　or　antisymmetric　structures　in　the　future.