Abstract: Agricultural carbon emission has been one of the major sources of carbon emission in the era of peak carbon and carbon neutrality. Therefore, it is of great significance to clarify the status quo of agricultural carbon emission in recent years, particularly for the spatial-temporal changes and influencing factors. Taking Jiangxi Province of China as the typical study area, the measurement system of agricultural carbon emission was established to calculate the agricultural carbon emission in 81 counties from 2000 to 2020. Four major carbon sources were selected as the paddy field planting, agricultural investment inputs, soil plowing, as well as livestock and poultry farming. The spatial pattern of agricultural carbon emission was analyzed by the spatial autocorrelation and center of gravity transfer at county level. The relevant influence factors were then determined by logarithmic mean Divisia index (LMDI). The results were summarized as follows: 1) The agricultural carbon emission in the study area was ranged from 10.98 to 14.72 million tons. An outstanding increasing trend was found in the agricultural carbon emission on the whole, whereas the carbon emission intensity was in an overall decreasing trend. The carbon emission intensity of planting industry showed a decreasing trend, ranging from 2.50 to 3.87 tons per ten thousand Yuan. Similarly, the carbon emission intensity of animal husbandry also showed a decreasing trend, ranging from 0.76 to 2.03 tons per ten thousand Yuan. Particularly, the total carbon emissions of each carbon source and the proportion in total agricultural carbon emissions were ranked in the descending order of: the paddy field planting (8.07 million tons, 61.15%), livestock and poultry (2.43 million tons, 18.57%), agricultural investment inputs (2.37 million tons, 18.02%), soil plowing (0.27 million tons, 2.26%); 2) There was the apparent spatial characteristic of agricultural carbon emissions. For example, the high carbon emission areas were concentrated in the Poyang Plain and the Jitai Basin. Furthermore, the spatial distribution of agricultural carbon emission intensity was from the relative dispersion to concentration in the Northern, whereas, the carbon emission intensity in The Southern was relatively low. The center of gravity of total carbon emissions shifted northward, where the carbon emission in The Northern was higher than that in The Southern Jiangxi Province. 3) Agricultural production efficiency improvement was the most important factor to restrain the sustained growth of the agricultural carbon emissions. The factors were ranked on the agricultural carbon emission reduction and the proportion in the total agricultural carbon emission reduction: the agricultural production efficiency (18.28 million tons, 56.57%), regional industrial structure (12.65 million tons, 39.15%), rural population size (0.86 million tons, 2.66%), agricultural industrial structure (0.52 million tons, 1.62%). Overall, the area order was given in the absolute value of agricultural carbon emission reduction by each factor from large to small: the North, the Middle, the South. The finding can provide the scientific strategy to estimate agricultural carbon emissions in Jiangxi Province, even the major grain producing areas.