On account of the characteristics of water in Taihu during high algal period, the pilot investigation was conducted with the combination of ultrafiltration membrane with coagulation, pre oxidation technology or adsorption technology. The results show that the quality of influent water from the three combination processes: coagulation precipitation ultrafiltration membrane, potassium permanganate coagulation precipitation ultrafiltration membrane, potassium permanganate coagulation precipitation power activated carbon ultrafiltration membrane are preferred, with turbidity lower than 0.1 NTU, algae control in the number of 2.5 × 104/L, and other measured targets meet the drinking water standards (GB 5749—2006). The organic matter of high algal water mainly includes hydrophobic organic compounds which are major factors leading to membrane fouling. The effective pre treatment before ultrafiltration membrane can prevent hydrophobic organic compounding into the membrane pore, which will effectively ease the membrane fouling during the high algal period.