By using emergy theory and method ,the structure of emergy input and output of agro2ecosystem in Chengde were analyzed. A paradigm about emergy flows of the agro2ecosystem of Chengde was presented together with the main emergy flows and emergy analysis indicesof the system in 2005. The result showed that the natural renewable emergy investment flows affected the stability of agricultural production in Chengde. The human emergy was more than mechanical emergy. The crop emergy output showed that starch grain demand was still strong for the consumers. The emergy indices showed that there were lower productivity and development because of inputing less purchase emergy per unit of the free use of environmental resources. There was the potential for further development and utilization.