Abstract: Anaerobic digestion is one of the key technologies for modern wastewater treatment. In this paper, the control factors of anaerobic digestion are discussed based on the summarization of present research literatures. The mechanism of the effect of pH and Eh on anaerobic digestion is analyzed with microbiology and biochemistry theory. The equation describing the effect of pH variation on Gibbs free energy variationΔGis derived using Nernst equation, and the specific control conditions in engineering are summed up according to the present research achievements.