NOVELTY - Control of methane fermentation process involves adding organic raw material into methane fermentation system, and adjusting feed rate by monitoring the pH value of methane fermentation system, acetic acid concentration (A), propionic acid concentration (P), bicarbonate salinity (BA) and volatile fatty pH (IA). The organic loading rate is gradually increased by adding raw materials until the system reaches the maximum allowable organic loading rate of feed.    USE - Control of methane fermentation process (claimed).    ADVANTAGE - The method enables control of methane fermentation process with high yield.    DETAILED DESCRIPTION - Control of methane fermentation process involves adding organic raw material into methane fermentation system, and adjusting feed rate by monitoring the pH value of methane fermentation system, acetic acid concentration (A), propionic acid concentration (P), bicarbonate salinity (BA) and volatile fatty pH (IA). When the pH is 0.1-0.2, ratio (P/A) of acetic acid concentration and propionic acid concentration is 0.8-1.2, and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is 0.3-0.5, then methane fermentation system is unstable state and organic loading rate is controlled to 70%. The feed rate is reduced until the pH value is less than 0.1, ratio (P/A) of acetic acid concentration and propionic acid concentration is less than 0.8, and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is less than 0.3, and amount recovered material is controlled. When the pH is 0.2-0.3 (excluding 0.2), ratio (P/A) of acetic acid concentration and propionic acid concentration is 1.2-1.5 (excluding 1.2), and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is 0.5-0.7 (excluding 0.5), the methane fermentation system is in state of severe unstable, and feed rate is controlled to 30%. The feeding is continued until the pH value is less than 0.1, ratio (P/A) of acetic acid concentration and propionic acid concentration is less than 0.8, and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is less than 0.3, and amount recovered material is controlled. When the pH is more than 0.3, ratio (P/A) of acetic acid concentration and propionic acid concentration is more than 1.5, and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is more than 0.7, the methane fermentation system is in state of extreme instability. Then, feeding is stopped when pH value is less than 0.1, and ratio (P/A) of acetic acid concentration and propionic acid concentration is more than 0.8 and ratio (IA/BA) of volatile fatty pH and bicarbonate salinity is less than 0.3, and organic loading rate is gradually increased by adding raw materials until the system reaches the maximum allowable organic loading rate of feed. The raw material comprises manure, crop residue, food waste, fruit and vegetable waste, living organic waste and grass. The organic loading rate of is gradually increased to 0.1-0.5 kgVS/(m3.d). The maximum allowable organic loading rate is 6-8 kg VS/(m3.d). The methane fermentation system is continuous or semi-continuous anaerobic digestion reactor.