Polyethersulfone (PES) is widely used as an ultrafiltration (UF) membrane material in industrial production due to its excellent performance. However, its inherent hydrophobicity leads to severe membrane fouling issues during practical operation. In this study, focusing on the fouling issues of PES UF membrane, bismuth oxychloride (BiOCl) was chosen as the main nanomaterial. Ag NPs were introduced via photoreduction into BiOCl at the optimal ratio of polyvinylpyrrolidone (PVP) and BiOCl (wt%-0.3:100), resulting in the synthesis of Ag@BiOCl nanoparticles. These nanoparticles were then blended into the PES casting solution and fabricated into composite UF membranes using the reverse thermally induced phase separation (RTIPS) method. Analysis of UV-vis characterization results revealed that the introduction of Ag NPs widened the visible light absorption range of the composite material from 414.30 nm to 508.62 nm. PL spectroscopy results indicated that Ag NPs effectively inhibited the recombination of photogenerated electron-hole pairs, significantly enhancing the photocatalytic activity of Ag@BiOCl. Additionally, the introduction of Ag NPs induced the generation of oxygen vacancies (OVs) on the surface of the composite membrane. Under visible light, the contaminated composite membrane drove the OVs in the photocatalytic material to generate hot electrons (h