Magnetically　separable　Fe3O4/hTiO2/g-C3N4　composites　were　successfully　constructed　through　coating　polymethylacrylic　acid　sacrificial　interlayer　by　the　reflux-precipitation　polymerization　and　subsequent　TiO2　outer　layer　by　sol-gel　method　over　magnetic　Fe3O4　nanospheres,　calcining　process　and　forming　composites　with　gC3N4　in　sequence.　The　formation　mechanism　of　unique　composites　was　proved　by　TEM,　XPS,　VSM,　XRD　and　EDX　mapping　characterization.　Their　photocatalytic　activity　was　investigated　by　the　solar　photodegradation　of　organic　dyes.　The　results　revealed　the　photocatalytic　performance　of　Fe3O4/hTiO2/g-C3N4　for　degrading　methylene　blue　(95.0　%,　120　min)　under　simulated　sunlight　irradiation　(Xe　lamp,　500　W)　was　much　better　than　gC3N4　(71.1　%,　120　min)　and　Fe3O4/hTiO2　(40.3　%,　120　min).　The　boosted　property　is　presumably　ascribed　to　the　synergetic　interaction　of　multiple　components　and　effective　separation　of　the　photoproduced　electron-hole　pairs　between　g-C3N4　and　TiO2,　which　was　verified　using　photocurrent　and　EIS　analysis.　On　the　basis　of　the　scavenging　studies　of　radicals　(h+,　center　dot　O2-　and　center　dot　OH),　the　mechanism　of　the　boosted　photocatalytic　performance　was　put　forward.　The　degradation　pathways　of　methylene　blue　were　also　proposed　by　identifying　reaction　intermediates　produced　during　photocatalysis.　More　significantly,　the　composites　presented　excellent　magnetic　responsive　property　owing　to　the　magnetic　Fe3O4.　The　superior　recyclability　was　confirmed　by　cyclical　photocatalytic　experiments　with　the　help　of　an　external　magnet,　which　is　crucial　for　the　sustainable　and　green　application　of　photocatalysts.