A study was conducted to clean up polluted water from Taihu Lake using a combination of preozonation, traditional methods, and ultrafiltration. The results showed that this process effectively removed impurities like turbidity, CODMn, UV254, and DOC from the water. It also got rid of particles, bacteria, and E.coli, while reducing iron, manganese, and algae levels to below standard limits. Compared to just using ultrafiltration, this combined method increased the stability of the process. Overall, the combined process can be used to treat polluted lake water effectively.