This study employed high-throughput sequencing to investigate the diversity and functional composition of bacterial communities in water and substrate samples,aiming to evaluate the role of arti-ficial floating island substrates in water remediation.The bacterial community structure,diversity pat-terns,and functional metabolic potential in both water and substrate samples were analyzed,and func-tional prediction was conducted to assess the influence of the substrate-based system on bacterial diver-sity and water purification performance.The results demonstrated that bacterial richness and diversity in the substrate samples were significantly higher than those in the water samples.Among the substrate treatments,the bio-cord substrate exhibited markedly higher bacterial richness,community evenness,and overall diversity compared with the composite substrate and the control water group.The relative abundances of Nitrospirota and Acidobacteriota were significantly increased in the substrate treatments,indicating that the substrates provided a favorable microenvironment for functional microorganisms and promoted the synergistic processes of nitrification and denitrification,thereby enhancing nitrogen re-moval efficiency.Moreover,the combined effect of substrates and aquatic plants effectively reduced the relative abundance of Cyanobacteria,thereby lowering the risk of eutrophication.These findings provide a scientific basis for the application of artificial floating island substrate systems in water quality restoration and further elucidate the adaptive strategies and ecological roles of bacterial communities and dominant functional taxa under different environmental conditions.