Abstract: Accurate regional ammonia emissions inventories are critical to developing effective air pollution control measures. Taking the Pan-Pearl River Delta (PPRD) region consisting of nine provinces: Fujian Province, Jiangxi Province, Hunan Province, Guangdong Province, Guangxi Zhuang Autonomous Region, Hainan Province, Sichuan Province, Guizhou Province, and Yunnan Province as the study area, based on the emission activities of 10 different ammonia emission sources, the ammonia emission inventory of PPRD from 2008 to 2020 was constructed by using the emission factor method. Meanwhile, the ammonia emissions in 2020 were presented with 1 km × 1 km spatial grid distribution through ArcGIS software. The results show: (1) During the study period of 2008-2020, ammonia emissions in PPRD Region generally showed a stable trend, ranging from 2685.40×10³ to 2839.35×10³ t, with an annual variation rate of −1.42% to 1.88%; agricultural sources accounted for 92.23% to 93.79% of the total ammonia emissions, while the non-agricultural sources accounted for 6.21% to 7.77%. (2) In 2020, Sichuan Province had the largest ammonia emissions, 689.07×10³ t, accounting for 24.53% of the total ammonia emissions in the study area, followed by Yunnan Province and Hunan Province with emissions of 14.70% and 13.90% respectively. Laying hens, beef cattle and pigs were the main contributors to ammonia emissions from livestock and poultry farming, with ammonia emissions of 661.75×10³, 339.88×10³ and 310.97×10³ t respectively; urea accounted for 97.17% of ammonia nitrogen emissions from nitrogen fertilizer application. (3) In 2020, the spatial distribution of ammonia emissions in PPRD Region was significantly different, the high-intensity areas mainly concentrated in central of Sichuan Province, with emission intensity reaching up to 481.03 t/km²; the low-intensity areas were mainly distributed in the west of Sichuan Province and the northwest of Yunnan Province. (4) At the 95% confidence interval, the uncertainty range in 2020 was from −18.08% to 20.97%, of which the uncertainty in livestock and poultry breeding and fuel combustion was lower, ranging from −7.43% to 8.15% and −9.50% to 10.32%, respectively. Our study shows that the overall trend of ammonia emissions in PPRD Region changed little over the years, with livestock and poultry farming being the main emission source. Strengthening the general implementation of ammonia emission reduction technologies in the livestock sector will be a possible way to significantly reduce ammonia emissions.