Abstract: Abstract: Grain drying is not only restrained by human operation behavior, but also influenced by a lot of objective factors, such as environmental factors, grain physical properties, and grain flow characteristics, as well as the processing technology and geometry of the dryer. In order to objectively and rationally evaluate the energy efficiency of the drying system, and realize the high efficiency and energy saving of grain drying, based on the heat and mass balance calculation of drying system, as well as the evaluation method of thermal efficiency and exergy efficiency, the energy utilization degree of counter-flow continuous drying process system was investigated under the change of airflow condition. The test results showed that the energy utilization effect of each drying segment in the dryer was better under the experimental condition. In high temperature drying segment, the exhaust gas heat loss and heat loss of drying chamber were not higher than 6.68% and 11.09%, respectively, and the thermal efficiency and exergy efficiency were not less than 83.02% and 68.1%, respectively. In low temperature drying segment, the exhaust gas heat loss and heat loss of drying chamber were not higher than 21.26% and 9.37%, respectively, and the thermal efficiency and exergy efficiency were not less than 69.37% and 56.22%, respectively. In cooling segment, due to that the grain temperature was higher than air temperature, which meant that the air had obvious cooling and dehydration effect on the grain. The average thermal efficiency and exergy efficiency of drying system were 80.24% and 64.52% respectively, which showed that the energy matching effect during grain drying process was good. The heat loss of drying chamber initially was 1.86% while 21.26% in later stage. The corresponding thermal efficiency of drying chamber reduced from 89.09% to 69.37%. The exergy efficiency of drying chamber reduced from 72.55% to 56.22%, which indicated that the energy consumption of grain drying not only had subjective exergy, but also contained objective exergy, and the evaluation of drying process and dryer energy utilization efficiency could not just stay on the subjective thermal efficiency, and should consider the effect of objective energy. Test showed that the average unit heat consumption of grain was 2 944.6 kJ/kg, and compared with the national standard, which was less than 7 400 kJ/kg, the highest energy saving could reached 60.2%. At the same time, the grain temperature was raised slowly with the moisture content decreasing during grain drying, and the highest temperature did not exceed 38.0 ℃, close to or below the glass transition temperature of grain, which showed that with the reasonable design of the grain drying process, the drying quality of grain could be better ensured. The results provide an analytical reference to improve grain drying efficiency and explore the ways of energy saving drying, as well as provide reference to design the grain drying process system and establish energy efficiency evaluation standard for grain drying.