Energy is the material basis for social development and is closely related with the economy. Energy shortage, a low utilization rate of energy and the deterioration of the environment have become the main restrictions of economic development in China. Therefore, studying energy efifciency has a practical signiifcance for developing a harmonious and sustainable energy economy and building a conservation-minded and harmonious society. Here, based on the three-stage DEA model we analyzed the energy efifciency of 29 provinces in China in 2009, set up an evaluation index system of energy efifciency to compare differences in energy efifciency among regions and provide regions with theoretical guidance to adjust energy consumption strategy and improve energy efifciency. We divided technical efifciency into pure technical efifciency and scale efifciency, analyzed energy efifciency with its numerical value and added environment variables to perfect the results. We found that scale efficiency is overestimated before eliminating external factors and environment variables and pure technical efifciency is underestimated. To solve this problem, regions should expand the scale of the enterprises and pay more attention to energy efifciency. The scale returns of most provinces in the third stage are increasing （except Shandong province）, which shows that many enterprises are too smal to relfect the economy scale. Therefore, al regions except Shandong should increase their energy inputs to obtain the economy scale of energy utilization. From a regional perspective, eastern energy efifciency is highest and western is the lowest. Al regions should increase the size of enterprises to realize the scale economy. Central and western regions in China should strengthen mutual cooperation, bring into play their respective advantages, exploit new energy and new technology and improve the utilization ratio of energy.
