Surface　plasmon　resonance　(SPR)　of　metal　nanostructures　has　broad　application　prospects　in　the　fields　of　sensing,　energy,　catalysis　and　optics.　This　paper　reports　a　graphene-assisted　method　for　preparing　large-scale　single-crystal　Ag(111)　nanoparticle　(NP)　arrays　based　on　the　ion　implantation　technique.　By　surface　periodic　patterning　treatment　and　annealing　of　the　implanted　sample,　regularly　arranged　Ag　NPs　can　be　prepared　on　the　sample　surface.　A　new　application　for　graphene　is　proposed,　that　is,　as　a　perfect　barrier　layer　to　prevent　metal　atoms　from　evaporating　or　diffusing.　All　the　Ag　NPs　show　(111)　crystal　orientation.　Besides,　the　Ag　atoms　are　covered　by　graphene　immediately　when　they　precipitate　from　the　substrate,　which　can　prevent　them　from　being　oxidized.　On　the　basis　of　this　structure,　as　one　of　the　applications　of　the　metal　SPR,　we　have　measured　the　surface-enhanced　Raman　scattering　effect　and　found　that　the　G　peak　of　the　Raman　spectrum　of　the　graphene　achieved　about　20　times　enhancement.