Displacement　damage　to　the　structure　and　properties　of　phase-change　materials　caused　by　high-energy　particle　radiation　is　a　major　challenge　to　the　development　of　optical　storage　systems　for　space　applications.　In　this　paper,　a　10　MeV　proton　irradiation　was　carried　out　on　an　amorphous　and　crystalline　phase-change　material　of　Ge2Sb2Te5　(namely　a-GeSbTe　and　c-GeSbTe)　respectively,　and　radiation-induced　local　structural　and　optical　property　changes　were　then　studied　using　Raman　spectroscopy　and　X-ray　photoelectron　spectroscopy　as　well　as　a　spectrophotometer.　The　results　indicated　that　proton　bombardment　caused　the　partial　breaking　of　the　Sb-Te　and　Ge-Te　bonds　in　both　the　a-GeSbTe　and　c-GeSbTe　samples,　but　with　a　greater　number　of　broken　bonds　in　c-GeSbTe　which　led　to　an　obvious　drop　in　optical　reflectivity　together　with　an　enhanced　surface　roughness　as　compared　to　a-GeSbTe.　SRIM　simulations　further　verified　that　c-GeSbTe　experienced　a　higher　degree　of　displacement　damage,　with　peak　damage　values　up　to　3.3　×　10-5　dpa.　Meanwhile,　vacancies　in　a-GeSbTe　tended　to　gather　toward　the　film　bottom,　while　those　in　c-GeSbTe　were　commonly　clustered　near　the　film　middle.　This　paper　provides　crucial　insights　into　understanding　the　response　of　Ge2Sb2Te5　to　proton　irradiation.　IEEE