Abstract: The study site is Changling, Jilin Province, located in the ecotone between agriculture and animal husbandry in Northeast China. Agricultural ecosystem of the region was studied systematically. The structure of the agricultural ecosystem was optimized through linear program model. Optimization model was developed according to the results. The total net profit per hectare cropland is approximately doubled after optimization. Therefore, the structure of agricultural ecosystem in the region is reasonable and net profit has been increased significantly after optimization. The model is helpful for restructuring the agricultural ecosystem in the region.