In order to investigate low-temperature influence on the SBR process and sludge bulking, the SBR process pollutants removal effect was studied with normal and low temperature. The experimental results showed that the effluent water quality was better with temperature 22~24°C and DO 2mg/L. During this period, sludge bulking did not happen and the SVI was stable for 30d at the range of 60~80mL/g. The sludge settlement became worse when the temperature sharply dropped to 13~15°C and DO concentration was unchanged, the SVI was sharply increased to 240~270mL/g from 60~80mL/g in several cycles, and it was in the state of sludge bulking for 60d. The system denitrification effect was almost lost and the nitrification effect had been seriously affected. When the temperature returned to normal, the nitrification effect was gradually improved. The effluent water was clear and the SVI returned gradually, but the SVI eventually maintained at 150mL/g without retune to previous range.