The invention discloses a method of preparing an antibacterial anti-pollution ultrafiltration membrane by adopting a silver-loaded nano composite material. The method comprises the following steps: preparing a nano material water dispersion solution, adding trihydroxymethyl aminomethane and dopamine hydrochloride, stirring and reacting for 2 to 12 hours, centrifugally washing, then drying to obtain a polydopamine-modified nano material; preparing a mixed solution containing the polydopamine-modified nano material, a silver-ammonium solution, a stabilizer and water, stirring for 2 to 12 hours, centrifugally washing, and then drying to obtain the silver-loaded nano composite material; dispersing the silver-loaded nano composite material in an organic solvent, adding a membrane material, stirring, completely dissolving the membrane material, and standing to obtain a membrane casting solution; and scraping the membrane casting solution into a flat membrane by utilizing a flat membrane scraping machine, immersing in a coagulating bath, and carrying out a phase conversion to obtain the antibacterial anti-pollution ultrafiltration membrane. The ultrafiltration membrane has good hydrophilia, durable antibacterial performance and excellent anti-pollution performance, has good antibacterial and sterilization effect for colibacillus, bacillus subtilis and the like; moreover, the silver nano particles stably exist in the antibacterial anti-pollution ultrafiltration membrane.