In　this　study,　a　novel　composite　based　on　bismuth　oxide,　reduced　graphene　oxide　and　titanium　dioxide　(labeled　as　BRGT)　was　utilized　for　visible　light　photocatalysis　to　mitigate　ultrafiltration　membrane　fouling　caused　by　natural　organic　matter　(NOM).　The　results　show　that　the　coexistence　of　NOM　and　the　BRGT　composite　(without　photocatalysis)　did　not　aggravate　membrane　fouling,　and　the　membrane　preferentially　retained　a　high　molecular　weight,　hydrophobic　component　of　NOM　that　formed　a　dense　cake　layer　with　BRGT　composite.　As　the　photo-catalysis　time　increased,　the　extent　of　membrane　fouling　was　alleviated.　The　maximum　specific　flux　recovered　from　0.21　to　0.73　at　60　min,　and　the　hydraulic　reversible　and　irreversible　resistances　ere　1.15　x　1010　and　4.23　x　1010　m-1,　respectively.　The　reduction　of　NOM　in　the　feed　water,　especially　the　removal　of　UV254,　played　a　significant　role　in　the　alleviation　of　membrane　fouling.　Additionally,　the　changes　in　the　properties　of　NOM,　including　the　reduction　of　fluorescent　humic　and　protein/polyphenol　components　corresponding　to　reversible　and　irreversible　fouling,　respectively,　the　photo-degradation　of　high　molecular　weight　NOM　into　low　molecular　weight　NOM　(such　as　low　molecular　weight-acids),　and　the　conversion　of　hydrophobic　fractions　into　hydrophilic　fractions,　contributed　to　the　mitigation　of　membrane　fouling.　We　also　found　a　strong　negative　correlation　be-tween　the　roughness　of　the　cake　layer　and　irreversible　fouling.　Overall,　the　changes　in　the　properties　of　NOM　in　feed　water　can　hinder　or　even　inhibit　the　formation　of　the　cake　layer,　and　the　use　of　visible　light　photocatalysis　of　the　BRGT　composite　has　great　potential　to　alleviate　ultrafiltration　membrane　fouling　caused　by　natural　organic　matter.