Heterostructural　materials　have　the　advantage　of　extreme　low　switching　energy　between　states　and　hence　are　expected　to　be　applied　in　photonic　devices,　whose　optical　performances　are　vital　to　explore　in　advance.　In　this　paper,　crystal　structures　of　TiTe2/Sb2Te3　heterostructural　films　and　their　effects　on　optical　properties　were　clarified　from　the　aspects　of　in-plane　strain,　resonant　bonding　and　charge　redistribution　by　experiments　and　first　principle　simulations.　Larger　strain　in　Sb2Te3　sublayer　tended　to　decrease　reflectivity　and　refractive　indexes,　while　huge　resonant　bonding　effect　was　beneficial　to　improve　the　optical　parameter　deviations.　Charge　analyses　showed　that　crystalline　optical　property　variations　were　actually　deriving　from　the　electron　redistribution　differences　especially　near　the　heterostructural　Te　center　dot　center　dot　center　dot　Te　gap,　which　also　accounted　for　experimental　reflectivity　order.　Finally,　based　on　the　resonant　bond　effects　and　surrounding　electron　density　after　stimuluses,　five　optical　levels　with　identifiable　optical　contrasts　(n　and　Delta　R)　were　achieved　in　1/2　model　for　uses.　The　present　study　sheds　new　light　on　optical　properties　of　TiTe2/Sb2Te3　and　paves　the　way　for　potential　multi-state　applications　of　heterostructure　in　photonic　and　storage　devices.　(C)　2021　Elsevier　B.V.　All　rights　reserved.