Zhengning County in Gansu Province, the cradle of traditional farming culture, is abundant in coal resource and solar energy, but it is ecologically fragile and has significant ecological service function, therefore facing the dual pressure of resource exploitation and environmental protection. Based on the analysis of main emergy indices of Zhengning eco-economic system during the past 20 years, this paper evaluates the efficiency of material metabolism and the capability for sustainable development, and puts forward sustainable management to promote the rapid and harmonious development of west China's counties.