Banana plantation is an important type of agro-ecosystem in the tropics, and it is important to carry out a quantitative assessment of the carbon footprint of the banana growing process for the development of low-carbon agriculture to cope with global warming. The carbon footprint of two banana cultivation processes was assessed using the life cycle assessment method through field trials and farmer surveys in Chengmai County, Hainan Province, China. The results showed that: (1) N2O emissions caused by the application of nitrogen fertilizers and compound nitrogen fertilizers were the largest source of carbon emissions from banana plantation farmland, and the production and transportation of common compound fertilizer were the second largest source of carbon emissions. Banana fruits and plants were the main contributors to carbon fixation in banana plantation ecosystems, with about 24.72 t CO2 eq hm-2 for Musa paradisiaca AA, and 34.66 t CO2 eq hm-2 for M. AAA Cavendish var. Brazil. (2) The annual carbon emissions of Musa paradisiaca AA and M. AAA Cavendish var. Brazil farmland systems were 35.40 t CO2 eq·hm-2 and 43.83 t CO2 eq·hm-2, respectively, and the annual carbon fixation was 38.23 CO2 eq·hm-2 and 48.17 CO2 eq·hm-2, respectively. The banana plantations had a negative carbon footprint per unit area, showing a net carbon sink function. (3) Banana is a plant with high carbon emission and strong carbon fixation capacity. Scientific management in the field can achieve the decrease of agricultural inputs, high quality and abundant agricultural products, and the reduction of carbon footprint of farmland.