A　rational　design　of　highly　efficient　photothermal　agents　that　possess　excellent　light-to-heat　conversion　properties　is　a　fascinating　topic　in　nanotheranostics.　Herein,　we　present　a　facile　route　to　fabricate　size-tunable　reduced　graphene　oxide　(rGO)-coated　gold　superparticles　(rGO-GSPs)　and　demonstrate　their　dual-enhanced　photothermal　conversion　properties　for　photoacoustic　imaging　and　photothermal　therapy.　For　the　first　time,　graphene　oxide　(GO)　was　directly　used　as　an　emulsifying　agent　for　the　preparation　of　gold　superparticles　(GSPs)　with　near-infrared　absorption　by　the　emulsion　method.　Moreover,　GO　spontaneously　deposited　on　the　surface　of　GSPs　could　also　act　as　the　precursor　of　the　rGO　shell.　Importantly,　both　the　plasmonic　coupling　of　the　self-assembled　gold　nanoparticles　and　the　interaction　between　GSPs　and　rGO　endow　rGO-GSPs　with　enhanced　photothermal　conversion　properties,　allowing　rGO-GSPs　to　be　used　for　sensitive　photoacoustic　detection　and　efficient　photothermal　ablation　of　tumours　in　vivo.　This　study　provides　a　facile　approach　to　prepare　colloidal　superparticles-graphene　hybrid　nanostructures　and　will　pave　the　way　toward　the　design　and　optimization　of　photothermal　nanomaterials　with　improved　properties　for　theranostic　applications.　©　The　Royal　Society　of　Chemistry　2016.