Abstract: In order to improve the hydrolysis step in the process of excess sludge anaerobic digestion, static batch test was conducted to investigate the effect of low temperature treatment on the actual domestic sludge generated. The research was to investigate the effect of low temperature on organic matter solubilization, soluble carbohydrates and soluble protein molecular weight changes and the changes of dewaterability on the condition that the treated time between 10 and 80min and the treated temperature between 50 and 90℃. The results show that the concentration of soluble chemical oxygen demand, the soluble carbohydrates and the soluble protein get the highest concentration on 80min and 90℃,70min and 90℃, 40min and 70℃, increase 15.5 times,19.2 times and 5.2 times to the raw sludge respectively. In the range of 50-90℃,through gel permeation chromatography method for analyzing molecular weight of the SC and SP, the results show thatminimum molecular weight of the SC changed from 163u to 2.5u, and SP changed from 1.41u to 0.26u with the rise of temperature and time. Capillary suction time (CST) was investigated to evaluate the sludge dewaterability, and the value of CST have significant rise after 80℃, increase to 108.8s on 80min,70℃and increase to 375.7s on 80min and 90℃. According to the above research, there comes a conclusion that, the optimum condition is 70℃ and 30minutes.