Abstract: Based on the theories and methodologies of emergy analysis, an assessment index system including emergy yield ratio, emergy density, emergy/currency (US dollar) ratio, environmental loading rate, and emergy sustainability index was established, and a quantitative study on the development trend of the eco-economic system of Chengdu, Sichuan Province of Southwest China from 2005 to 2009 was conducted. In the study period, the emergy yield ratio of the eco-economic system was in declining, the environmental loading rate increased from 17.49 to 37.77, and the emergy sustainability index decreased from 0.26 to 0.06. With the rapid social and economic development, the pressure on the environment was increasing, which hampered the sustainable development of the eco-economic system. It was crucial for Chengdu to optimize its industries structure, improve its emergy use efficiency, promote its clean production, establish an industrial chain of circular economy, and enhance the expansion and implementation of high technologies in depth and scope.

Key words: Loess Plateau, fine root, soil moisture, soil property.