To develop a feasible method for inhibiting methanogenesis while enhancing fermentative hydrogen production in anaerobic organic wastewater fermentation process, a continuous-flow stirred tank reactor (CSTR) a methane production feature was introduced and used as the baseline condition. The CSTR was operated at (35±1) ℃ with an influent COD 7 000 mg／L and a hydraulic retention time (HRT) 8 h throughout the performance test. When the pH in the CSTR decreased from 65-72 to 60-65, the methane yield decreased remarkably and could not be inspected in the biogas at last, while the percentage of hydrogen in biogas kept at a low level less than 3％. When the CSTR operated with a lower pH 40-50, the acidogenesis was further enhanced with a total organic intermediate of 2 052 mg／L, dominated by ethanol and acetic acid, indicating a typical ethanoltype fermentation established in the CSTR. During the ethanoltype fermentation process, a biogas yield of 26 L／d was obtained with a hydrogen percentage about 45％. The specific hydrogen producing rate of the anaerobic activated sludge reached at 167 L／(g·d) averagely.