NOVELTY - Performing anaerobic fermentation involves determining suitable range and related parameter for chicken manure as raw material at 25-37 degrees C in a continuous stirring reactor. The raw material and methane liquid are added into fermentation tank. The suitable conditions for the fermentation are, when a relux in the tank has microorganism activity without change in concentration of ammonia nitrogen and the conversion rate of ammonia nitrogen remains unchanged. The nitrogen exist as organic nitrogen. The hydrolysis process in the chicken converts nitrogen and forms substance.    USE - Method for performing anaerobic fermentation (claimed).    ADVANTAGE - The method enables to perform anaerobic fermentation, which has simple structure, equal reliability feature and prevents mathematics analysis tool.    DETAILED DESCRIPTION - Performing anaerobic fermentation involves determining suitable range and related parameter for chicken manure as raw material at 25-37 degrees C in a continuous stirring reactor. The raw material and methane liquid are added into fermentation tank. The suitable conditions for the fermentation are, when a relux in the tank has microorganism activity without change in concentration of ammonia nitrogen and the conversion rate of ammonia nitrogen remains unchanged. The nitrogen exist as organic nitrogen. The hydrolysis process in the chicken converts nitrogen and forms substance. The growth of microorganism and quantity of ammonia are ignored in reactor. The basic index setting of the fermentation tank has a0: a relux feedstock of organic nitrogen (g) by anaerobic digestion, which convetrs ammonia nitrogen of fermentation liquid (conversion rate is in between 0-1), an: relux number for n days, where feedstock organic nitrogen (g), where conversion of liquid ammonia nitrogen is performed (conversion rate is between 0-1) between, n: biogas reflow process run time (d), Yn: n day operation of the reflow process of biogas fluid ammonia concentration (g/L), A: total amount of nitrogen content of raw materials (g), which is daily added to the fermentation tank, V0: fermentor effective volume (L), V: daily access to material volume fermenter (L), R: reflux reflow process ratio (reflux ratio R=biogas reflux volume/total volume of the feed, between 0-1) and B= mathematical Model, where, H=(V0-(1-R)asteriskV)/V0 and T=A/V0.