Abstract: To scientifically calculate the agricultural carbon emission intensity and carbon reduction potential of Liaoning Province, a calculation system for agricultural carbon emissions was constructed based on statistical data from 2000 to 2021, covering five aspects: agricultural inputs, land use, soil carbon emissions, rice cultivation, and livestock farming, with 20 types of carbon sources. The carbon emissions were calculated using the carbon source coefficient method. The super-efficiency SBM model was applied to measure the agricultural carbon emission efficiency and the slack of input indicators in Liaoning Province. Furthermore, the LMDI model was used to decompose the main driving factors of agricultural carbon emissions, including agricultural production efficiency, agricultural industrial structure, agricultural economic development level, urbanization level, and agricultural labor scale, calculating their contribution values and exploring the carbon emission benefits. The results indicate that, over the 22-year period, the total agricultural carbon emissions in Liaoning Province continued to increase during the first 11 years, with reduced fluctuations in the last 11 years, and the agricultural carbon emission intensity also exhibited decreased volatility. The annual average contribution to agricultural carbon emissions from sources such as agricultural inputs, land use, soil carbon emissions, rice cultivation, and livestock farming were 36.72%, 0.23%, 11.36%, 5.12%, and 46.58%, respectively. Over the 22 years, agricultural carbon emission efficiency increased from 0.19 to 1.04, primarily due to the continuous optimization of input indicators, which manifested as a year-by-year reduction in slack values for indicators such as the agricultural labor force, crop planting area, agricultural machinery planting area, total agricultural machinery power, effective irrigation area, fertilizer usage, agricultural film usage, and pesticide usage. The driving factors of agricultural carbon emissions were found to be the agricultural economic development level and agricultural labor scale, with cumulative carbon emission effects of 12,642.12 thousand tons (54.63%) and 387.998 thousand tons (1.68%), respectively. The driving factors for carbon reduction were agricultural production efficiency, agricultural industrial structure, and urbanization level, with cumulative carbon emission effects of −9,596.26 thousand tons (41.47%), −344.98 thousand tons (1.49%), and −169.86 thousand tons (0.73%), respectively. It is recommended to achieve low-carbon, high-quality agricultural development in Liaoning Province by reducing fertilizer usage in crop cultivation, optimizing livestock farming management, improving agricultural technical efficiency, rationally adjusting the operational scale, and promoting agricultural structural adjustments.