This paper elaborates the mutual relation of energy, economy, environment and sustainable development,
analyzes the key factors affecting energy efficiency. By determining the goal and connotation of energy efficiency, this
paper establishes the evaluation model of energy efficiency, and constructs the energy utilization efficiency evaluation
system of energy supply, economic growth, environmentally friendly and sustainable development (3E&D). This index
system not only can be applied to the evaluation of energy efficiency and the forecast of energy consumption, but also can
be used for guiding energy saving and emission reduction, and it has wide applicability.