Ammonia is the only alkaline gas in the atmosphere. Reducing ammonia emissions plays an important role in controlling atmospheric pollution. Livestock and poultry breeding industry is an important source of ammonia emissions. Scientific assessment of ammonia emissions and reduction potential in different links is of great significance. In this paper, the ammonia emission factors of different livestock and poultry breeding houses in China and abroad, the main emission reduction technologies and efficiency were summarized. Combined with the number of mechanical ventilation farms and the animal population of major livestock and poultry obtained from the second national pollution source census, the ammonia emission reduction potential of exhaust air from mechanical ventilation livestock farms in China was analyzed. The results show that the reduction potential of ammonia emission from mechanically ventilated livestock houses in China is 265.6 thousand tons; pigs, laying hens and broilers were the three main sources of livestock and poultry, and their emission reduction potential were 101.8 thousand tons, 77.3 thousand tons and 67.5 thousand tons, respectively. The emission reduction potential of the three livestock and poultry types accounted for 92.8 %. Regionally, the main implementing regions are East China, South Central and North China, with ammonia emission reduction potential accounting for 35.1%, 26.9% and 14.9%, respectively. It is proposed to carry out the construction of ammonia emission reduction facilities in mechanical ventilation barn of pig, laying hens and broiler, which can provide guarantee for the national ammonia emission reduction and the improvement of atmospheric environmental quality. [ABSTRACT FROM AUTHOR]