Abstract: Pulping black liquor treated by the extremophiles from sludge of black liquor pool was discussed. The influence of anaerobic decomposition by the process conditions such as black liquor, sludge (V/V), black liquor concentration, pH and temperature was discussed. The results showed: T=30~35℃, pH=6.5~7.2 was the optimal process condition. The ratio of removal organic was rather high. In addition, anaerobic decomposition of aldonic acid was adapted for the condition of high temperature and stronger acidity (T>50℃, pH<6). Moreover, parts of high-molecular lignin was degraded in the biological reaction.