Natural　organic　matter　(NOM)　can　impede　the　removal　of　organic　micro-pollutants　(OMPs)　through　several　mechanisms,　including　inner　filter　effect,　competition　with　the　target　OMP,　and　radical　scavenging,　during　synchronous　adsorption/photocatalysis　of　multi-functional　composites.　In　this　study,　the　fate　and　inhibitory　mechanisms　of　sulfamerazine　(SMZ,　a　model　OMP)　that　occurred　in　presence　of　seven　different　NOM　samples　(i.e.　three　standard　NOM　surrogates,　a　river　water　sample,　a　carbon　filter　effluent　and　two　different　sand　filter　effluents)　during　the　adsorption/photocatalysis　by　a　composite　of　Bi2O3-TiO2　supported　on　powdered　activated　carbon　(Bi2O3-TiO2/PAC,　abbreviated　as　BTP)　when　exposed　to　visible　light　irradiation　were　revealed.　The　results　indicated　that　adsorption　played　a　greater　attribution　than　photocatalysis　on　SMZ　removal.　The　primary　impediment　to　the　adsorption　and　photocatalytic　degradation　of　SMZ　was　attributed　to　the　presence　of　terrestrial-derived,　humic-like　NOM　fractions　with　high　aromaticity.　The　adsorption　efficacy　of　SMZ　was　weakened　by　the　absorption　of　NOM　and　its　degradation　products　onto　the　BTP　surface.　The　inner　filter　effect,　competition　between　NOM　and　SMZ,　and　radical　scavenging　were　responsible　for　the　reduced　photocatalysis　of　SMZ.　In　the　cases　of　real　water　matrices,　the　presence　of　inorganic　anion　and　co-existed　NOM　reduced　the　removal　of　SMZ.　In　summary,　the　findings　of　this　work　offer　a　comprehensive　comprehension　of　the　impact　of　NOM　fractions　on　photocatalysis,　emphasizing　the　necessity　to　examine　the　interplay　between　NOM　and　background　inorganic　constituents　in　the　degradation　of　OMP　via　adsorption/photocatalysis.