In　recent　years,　tremendous　research　efforts　have　been　made　towards　developing　graphene　(GR)-based　nanocomposites　for　photocatalytic　applications.　In　this　work,　surface-coarsened　TiO2　nanobelts　(SC-TNBs)　closely　enwrapped　with　monodispersed　Ag　nanoparticles　(NPs)　and　GR　nanosheets　(i.e.　Ag/GR/SC-TNBs)　were　fabricated　using　a　facile　self-assembly　strategy　followed　by　photoreduction.　It　was　found　that　the　as-prepared　Ag/GR/SC-TNBs　ternary　heterostructure　exhibited　significantly　improved　photocatalytic　performances　under　irradiation　with　UV　light　in　comparison　with　blank　SC-TNBs　and　its　binary　counterparts　owing　to　the　formation　of　double　heterojunctions　among　the　components.　The　intimate　integration　of　Ag　NPs　and　GR　with　SC-TNBs　achieved　by　the　self-assembly　buildup　exerts　a　profound　effect　on　the　transfer　of　photogenerated　electrons　over　the　SC-TNBs　substrate　in　which　Ag　NPs　serve　as　an　efficient　＂electron　reservoir＂　and　GR　as　an　electron　transporter　and　collector,　thus　concurrently　prolonging　the　lifetime　of　the　photogenerated　electron-hole　pairs　and　resulting　in　the　remarkably　enhanced　photoactivity　over　the　Ag/GR/SC-TNBs　ternary　nanocomposite.　In　addition,　the　underlying　photocatalytic　mechanism　was　elucidated　and　the　primary　active　species　were　determined.