Jiangsu is a major agricultural province and grain producing area.The comprehensive accounting of the temporal dynamics and composition of carbon footprint of major crops could provide decision-making basis for environmental management and green development of the agricultural sector in Jiangsu province.In this paper,Life Cycle Assessment (LCA) was used to calculate the carbon emission intensity of rice,wheat,maize,soybean and rapeseed production processes in Jiangsu province during 1990-2019,and the temporal dynamics,composition and influencing factors of carbon footprints of these crops were analyzed.The results showed that the carbon footprint per unit yield of major crops in Jiangsu province decreased but the carbon footprint per unit area increased in recent 30 years.The carbon footprint per unit yield for different crops showed as rapeseed (1.74 kg (CO₂-eq)·kg^-1)> rice (1.36 kg (CO₂-eq)·kg^-1)> wheat (0.99 kg (CO₂-eq)·kg^-1)> maize (0.81 kg (CO₂-eq)·kg^-1)> soybean (0.64 kg CO₂-eq kg^-1).For the composition of carbon footprint,CH₄ emission (54.43%) and chemical fertilizer input (20.65%) were the two major sources for rice production,while chemical fertilizer input and soil N₂O emission are the most important sources for wheat,maize,soybean and rapeseed production.Random forest analysis showed that the variation of seed,nitrogen fertilizer and agricultural machinery input were the main driving factors for the interannual change of carbon footprints for different crops.Therefore,it is necessary to take targeted emission reduction strategies for different crop production and adjust agricultural inputs and process management in order to promote the green and efficient development of agriculture.