In order to quantitatively measure the carbon source/sink of farmland ecosystem in Henan Province, identify the important carbon emission sources in the process of agricultural development in Henan Province, and promote the development of green agriculture in Henan Province. In this paper, the carbon absorption, emission and carbon footprint of farmland in Henan Province from 2000 to 2017 were measured and their dynamic changes were analyzed. The results showed that the carbon uptake of farmland ecosystem in Henan Province was significantly higher than that of carbon emissions, which indicated that the farmland ecosystem in Henan Province had a strong carbon sink capacity; food crops contributed the most to total carbon uptake, and chemical fertilizer was the key factor affecting agricultural carbon emissions; the farmland ecosystem in Henan Province was in the form of carbon ecological surplus. The carbon footprint is low and the benefit of carbon footprint is high.