Exploring the sustainability of urban ecosystem is becoming a key area in global sustainable development. Urban metabolism is an effective analysis tool for the study of urban ecosystem. In this regard, how to evaluate the level of urban sustainable development and identify the key factors that affect urban metabolism is critical. Many studies on urban metabolism have been explored during the past half century, but few concerns about the key factors that affect urban metabolism. Therefore, this paper fills such a gap by combining emergy and Logarithmic Mean Divisia Index (LMDI) methods in order to analyze the sustainable development level and identify the driving forces of emergy utilization, respectively. A typical industrial city, Shenyang in northeast China, was chosen as a case study city in this paper. Results show that renewable resource utilization in Shenyang was very limited from 2000 to 2010, while nonrenewable resources and the imported resources increased rapidly. During this period, total emergy utilization of Shenyang increased from 8.52 × 1022 sej to 21.53 × 1022 sej, and emergy density increased with annual increasing rate of 10.34%, demonstrating a fast development of the economy and high level of resident's consumption. {LMDI} method was employed to analyze the driving forces of emergy consumption from the aspects of scale, structure and intensity. Results show that the rapid increase of emergy utilization in Shenyang was mainly caused by the expansion of economic scale, while emergy intensity greatly contributed to offset total consumption, and industry structure played a marginal role, with a minor value for its growth. Based upon these results, several policy recommendations were raised, including the use of more renewable and clean energy sources, a regenerative and preventative eco-industrial development approach, and capacity-building efforts, so that the overall environment pressure on urban development can be reduced.