Abstract: Anaerobic baffled reactor (ABR) was used as a hydrolysisacidogenesis unit, and INTdehydrogenase enzyme activity was used as an indicator to assess microorganism activity of each compartment of ABR. The relation between acidate bacteria activity and acidate ratio and the influence factors on acidate bacteria activity in each compartment has been discussed. The results shows that at the condition of OLR=2.4 kgCOD/（m³·d）,acidate is proportional to INTdehydrogenase enzyme activity of acidate bacteria in each compartment of ABR. The acidity rate of both the first room and the second room makes up to 73% of the total acidity rate and INTdehydrogenase activity in middle reactor is higher than in the bottom in each room.

Key words: anaerobic baffled reactor, acidate bacteria, INTdehydrogenase activity