To solve the problem of poor nitrogen removal capacity in winter, the hydrolysis-denitrification process combining hydrolytic acidification and denitrification process within single reactor was induced to treat municipal wastewater. The pilot test showed that the average removal rates of ammonia nitrogen of hydrolysis-denitrification process were 98.3% and 98.4% in winter and summer, respectively. And the average removal rates of total nitrogen were 65.2% and 68.0%, respectively. According to the nitrogen removal of pilot test, the activated sludge in hydrolysis-denitrification process and AAO process were studied to investigate the effect of temperature on specific denitrification rate and carbon source consumption rate. It is found that the temperature on activated sludge in hydrolysis-denitrification process had smaller effects than that in AAO process. In the two cases, namely the temperature are 25 ℃, 30 ℃, respectively, both denitrification rates of them was similar. However, when the temperature were 8℃、15℃ and 20℃, the specific denitrification rate of hydrolysis-denitrification sludge was 1.7、1.3 and 1.4 times the anoxic-denitrification sludge, respectively. In addition, the carbon source consumption rate of hydrolysis-denitrification sludge was 51.2%~81.7% of the anoxic-denitrification sludge.