Abstract: The study on the utilization coefficience of input energy in farmland ecosystem is an important part in sustainable agriculture research.The objective of this study was to determine the characteristics of energy flow in farmland ecosystem in which two crops (winter wheat and corn)were planted around a year under four tillage systems.The experiment was carried out in Hengshui,Hebei on a loam soil from 1992 to 1994.The results indicated that there were no significant differences between output energy,and the changes in entropy of thewinter wheat and corn farmland ecosystems under the four tillage systems.But input energy utilization rate of the zero tillage system was significantly higher than that of the other three tillage systems.