In order to treat the beet sugar factory wastewater and produce hydrogen, a low pH, ethanol-type fermentation process had happened in a continuous stirred tank reactor (CSTR) with an effective volume of 9.6 L in this experiment. The results showed that after inoculation with activated sludge and operation at organic loading rate (OLR) of 9 kgCOD/m3·d, hydraulic retention time (HRT) of 8h, influent pH value of 6.5 and temperature of 35°C for 30 days, the CSTR achieved stable ethanol-type fermentation. During this period of stable operation, the reactor showed a stable COD removal efficiency of 19.2% and hydrogen production rate of 0.1L/gMLSS·d. Effluent pH ranged from 4.0 to 4.5. The total amount of ethanol and acetic acid was 1384 mg/L, accounted for 81% of the total liquid products, which can be attributed to ethanol-type fermentation. The experimental results showed that the CSTR system had good operation stability and microbial activity, which led to high substrate conversion rate and hydrogen production ability.