A　crucial　and　desirable　objective　in　the　wastewater　treatment　field　is　to　design　photocatalysts　that　can　efficiently　remove　emerging　pollutants　while　also　being　environmental-friendly.　This　work　proposed　a　novel　graphene　quantum　dots/BiOBr　(GQDs/BiOBr)　heterojunction　with　strong　interfacial　interactions　through　a　hydrothermal　method.　Consequently,　in　just　140　min,　RhB　was　almost　entirely　photodegraded　by　the　GQDs/BiOBr　and　a　rate　constant　3.26　times　higher　than　pristine　BiOBr.　The　enhanced　photocatalytic　activity　of　GQDs/BiOBr　was　primarily　associated　with　strengthened　visible　light　absorption　and　improved　charge　transfer　efficiency,　as　demonstrated　through　both　experimental　characterizations　and　density　functional　theory　(DFT)　calculation.　Furthermore,　with　only　a　minor　alteration　in　the　surface　chemical　structure,　GQDs/BiOBr　retained　strong　photocatalytic　ability　after　five　cycles　(RhB　degradation　of　85.17　%).　The　construction　mechanism　of　S-scheme　heterojunction,　photogenerated　carriers＇　transfer　and　photocatalytic　mechanism　were　deduced　by　DFT　calculation.　The　results　derived　from　the　radical　trapping　experiments　as　well　as　electron　spin　resonance　(ESR)　indicated　that　the　presence　of　h(+)　and　center　dot　O-2(-)　were　crucial　for　the　degradation　process　of　RhB.　Finally,　possible　degradation　intermediates　had　been　identified　and　pathways　of　RhB　were　proposed,　and　the　results　of　the　toxicity　assessment　showed　that　ecotoxicity　could　be　reduced　or　even　eliminated.　This　effective　and　reliable　visible-light-driven　photocatalyst　may　be　applied　to　build　a　photocatalytic　degradation　system　for　the　environmentally　friendly　and　energy-efficient　removal　of　organic　pollutants.