Abstract: The content of ammonia nitrogen in anaerobic fermentation slurry produced from swine manure was measured to determine how the changes of fermentation conditions affect it. The results of experiments showed that the content of ammonia nitrogen in anaerobic fermentation slurry increased slowly with the increase of fermentation time when fermentation temperature was 15℃, and the content of ammonia nitrogen in anaerobic fermentation slurry increased quickly with the increase of fermentation time at 30℃ and 55℃. High material concentration was in favor of the rapid increase of ammonia nitrogen. Stir was in favor of the rapid increase of the content of ammonia nitrogen. Inoculation could promote the rapid increase of ammonia nitrogen in 1～2 days of fermentation. The content of ammonia nitrogen tended to decrease when pH value was 5, and the content of ammonia nitrogen tended to increase at pH 7 and pH 8.5. The optimization experiment indicated that material concentration was the most notable factor influencing the content of ammonia nitrogen. When fermentation time was 5 days, fermentation temperature was 30℃ and material concentration was 3.7%, the content of ammonia nitrogen was the highest.