The air flotation pump was used to replace the air compressor and dissolved air tank to prevent algae from accumulating on the fillers and reduce the maintenance. Through pilot, the removal effect of polluted raw water was studied and the improved grey system was used to analyze the influencing factors. The results showed that the DAF with the pump could operate stably. At high temperatures, the removal rates of turbidity and chlorophyll-a would be as high as over 91%. The total number of algae decreased from 20–32 to 1.5–3.5 million/L. The effluent turbidity was only about 3.5NTU, and UV254 was reduced by 15–23%. At low temperatures, the removal rates of turbidity and chlorophyll-a were still higher than 86%, and the total number of algae decreased from 4–8 million /L to 300,000 to 700,000 per liter. At high temperatures, the AGP of algae could reach 0.51 mg/m3, while at low temperatures it was only 0.02 mg/m3. When the PAC dosage increased to 20 mg/L, AGP could be significantly reduced. By normalizing and improving the grey correlation degree, the operating conditions of DAF on the removal effect from large to small were influent turbidity, reflux ratio, PAC dosage, water temperature and hydraulic load.