Abstract: In order to explore the eco-efficiency of agro-ecosystem around the Dongting Lake region of Hunan Province, and to reveal the interrelationships among the human, natural resources, and environment in the ecosystem, this paper analyzed the emergy structure, function, and efficiency of the agro-ecosystem, based on the emergy input-output data in 2009 and by using the emergy method of HT Odum. In the study period, this system was comparatively well developed in economy, and had a higher degree of mechanization and modernization. The fertilizer emergy and agricultural mechanical emergy accounted for 47.13% and 10.62% of the total, respectively, and the emergy density was 8.77×10¹¹sej·hm^-2·a^-1. The system emergy output was unbalanced, planting emergy output was dominant, while forestry and fishery emergy output was comparatively low. The monetary value of per capita emergy output was 31873.56 yuan, far greater than the per capita gross output value of regional economy in this system (24761.14 yuan), which indicated that the product pricing (especially the planting product pricing) of this system was evidently on the low side, and the value of natural resources and environment was not well reflected by the market. The environmental loading ratio was 1.74, sustainable development index was 1.40, and population bearing capacity was 4.91×10⁵ (the agricultural population in this region was 3.15×10⁶), showing that the system was full of vitality and development potential, the pressure from natural resources and environment was not so high, but the system was under too much employment pressure and the population bearing capacity was overloading. In sum, to further reduce the price scissors between industrial and agricultural products, to keep on protecting the market price of planting products, to adjust the agriculture industrial structure and product structure, and to transfer the surplus labor force would be the essential orientation of agriculture policy in this region.