Abstract: Based on the agricultural planting data in "Wenshan Prefecture Statistical Yearbook", the carbon emissions, carbon absorption, and net carbon sink of the farmland ecosystem in Wenshan Prefecture, Yunnan Province in a year were calculated using the greenhouse gas warming potential values published in the IPCC Sixth Assessment Report. Geographical information technology was used to analyze the spatial pattern of carbon sources and sinks in the regional farmland. Using the results of the calculation of the net ecosystem productivity of crops, the carbon sequestration capacity of different crops was analyzed and classified hierarchically.The results showed that the carbon emissions of the farmland ecosystem in Wenshan Prefecture were 1.1474 million tons, the carbon absorption was 2.2353 million tons, and the net carbon sink was 1.0879 million tons during 2021. The farmland ecosystem in Wenshan Prefecture as a whole played a carbon sink function; the farmland ecosystem in Wenshan Prefecture showed a carbon source state except for Funing County, and the rest of the county areas showed a carbon sink state. The carbon emissions of the farmland system showed a low northern and southern emission, and the emission gradually increased from west to east. The spatial layout of carbon absorption showed a gradually decreasing trend from north to south; among the crops, the highest carbon sequestration capacity was sugarcane, with an average carbon sequestration capacity of 9.56 t/hm²; the three crops of millet, rice, and corn had the second highest carbon sequestration capacity, with an average carbon sequestration capacity of 5.51 t/hm², 5.41 t/hm², and 5.06 t/hm² respectively; the remaining crops had a relatively weak carbon sequestration capacity and were in the third tier.