As　an　emerging　new　material,　graphene　has　aroused　the　great　research　interest.　How　to　improve　its　absorption　efficiency　is　one　of　the　hot　research　topics.　However,　currently　most　of　the　studies　concentrate　in　THz　band　or　middle-to-far-infrared　region:　the　research　in　the　visible　and　near-infrared　regions　is　rare,　which　greatly　limits　the　applications　of　graphene　in　opto-electric　fields.　In　order　to　improve　the　absorption　efficiency　of　single-layered　graphene　in　visible　and　near-infrared　band　and　realize　multi-channel　optical　absorption　enhancement,　we　propose　a　hybrid　structure　consisting　of　graphene-metal　grating-dielectric　layer-metal　substrate.　The　proposed　structure　can　realize　three-channel　light　absorption　enhancement　at　wavelengths　lambda(1)　=　0.553　mu　m,　lambda(2)　=　0.769　mu　m,　and　lambda(3)　=　1.130　mu　m.　The　maximum　absorption　efficiency　of　graphene　is　41%,　which　is　17.82　times　that　of　single-layered　graphene.　The　magnetic　field　distributions　of　the　hybrid　structure　at　three　resonance　wavelengths　are　calculated　respectively.　It　can　be　found　that　for　the　resonance　peak　lambda(1),　the　energy　of　light　field　is　distributed　mainly　on　the　surface　of　metal　grating,　which　is　the　characteristic　of　surface　plasmon　polariton　(SPP)　resonance.　Therefore,　it　can　be　judged　that　the　enhancement　of　graphene　absorption　in　this　channel　is　due　to　the　SPP　resonance　stimulated　by　metal　grating.　For　the　resonance　peak　lambda(2),　the　energy　of　the　optical　field　is　mainly　confined　into　the　metal　grating　groove,　which　is　the　remarkable　resonance　characteristic　of　the　Fabry-Perot　(FP)　cavity,　it　can　be　concluded　that　the　enhancement　of　the　optical　absorption　of　graphene　at　the　resonance　peak　lambda(2)　is　due　to　the　resonance　of　the　FP　cavity.　When　the　resonance　peak　is　lambda(3),　the　energy　of　the　light　field　mainly　concentrates　on　the　upper　and　lower　edges　of　the　metal　grating　and　permeates　into　the　SiO2　layer,　and　it　can　be　observed　that　there　are　energy　concentration　points　(reddish)　at　the　left　end　and　the　right　end　of　the　metal　grating　edge,　which　is　a　typical　magnetic　polariton　(MP)　resonance　feature.　Therefore,　the　enhancement　of　absorption　of　graphene　at　the　resonance　peak　lambda(3)　is　caused　by　the　MP　resonance　induced　by　the　metal　grating.　We　also　analyze　the　absorption　characteristic　(resonance　wavelength　and　absorption　efficiency)　dependence　on　structure　parameters　by　using　the　finite-difference　time-domain　(FDTD)　simulation.　Our　study　reveals　that　by　increasing　grating　width,　all　the　three　resonance　wavelengths　are　red-shifted,　and　the　absorption　efficiency　at　lambda(2)　and　lambda(3)　are　both　enhanced　whereas　the　absorption　efficiency　at　lambda(1)　almost　keeps　unchanged.　By　increasing　dielectric　layer　thickness,　lambda(2)　will　be　red-shifted　and　lambda(3)　will　be　blue-shifted,　whereas　the　absorption　efficiency　at　the　three　resonance　wavelengths　all　remain　constant.　By　increasing　graphene　chemical　potential,　none　of　the　wavelengths　of　the　three　absorption　peaks　is　shifted,　and　the　absorption　efficiency　at　lambda(3)　decreases.　According　to　our　findings,　we　optimize　structure　parameters　and　achieve　the　light　absorption　efficiency　larger　than　97%　at　the　three　channels　simultaneously,　which　can　make　metamaterial　absorbers.