As　a　promising　metal-free　photocatalyst,　graphitic　carbon　nitride　(g-C3N4)　is　still　limited　by　insufficient　visible　light　absorption　and　rapid　recombination　of　photogenerated　carriers,　resulting　in　low　photocatalytic　activity.　Here,　we　adjusted　the　microstructure　of　the　pristine　bulk-g-C3N4　(PCN)　and　further　loaded　silver　(Ag)　nanoparticles.　Abundant　Ag　nanoparticles　were　grown　on　the　thin-layer　g-C3N4　nanosheets　(CNNS),　and　the　Ag　nanoparticles　decorated　g-C3N4　nanosheets　(Ag@CNNS)　were　successfully　synthesized.　The　thin-layer　nanosheet-like　structure　was　not　only　beneficial　for　the　loading　of　Ag　nanoparticles　but　also　for　the　adsorption　and　activation　of　reactants　via　exposing　more　active　sites.　Moreover,　the　surface　plasmon　resonance　(SPR)　effect　induced　by　Ag　nanoparticles　enhanced　the　absorption　of　visible　light　by　narrowing　the　band　gap　of　the　substrate.　Meanwhile,　the　composite　band　structure　effectively　promoted　the　separation　and　transfer　of　carriers.　Benefiting　from　these　merits,　the　Ag@CNNS　reached　a　superior　hydrogen　peroxide　(H2O2)　yield　of　120.53　mu　mol/g/h　under　visible　light　irradiation　in　pure　water　(about　8.0　times　higher　than　that　of　PCN),　significantly　surpassing　most　previous　reports.　The　design　method　of　manipulating　the　microstructure　of　the　catalyst　combined　with　the　modification　of　metal　nanoparticles　provides　a　new　idea　for　the　rational　development　and　application　of　efficient　photocatalysts.