中文摘要：

能源短缺、利用率低、环境恶化已经成为制约我国经济发展的重要环节。本文运用三阶段DEA模型对中国29个省市2009年的能源效率进行了分析。文章将技术效率分为纯技术效率和规模效率,并利用其数值来分析能源效率,同时,加入环境变量来分析完善上述计算结果。结果表明,在剔除外部因素和环境变量以前规模效率被高估,纯技术效率被低估。大部分省在第三阶段计算出的规模收益是递增的,这说明很多企业规模较小不能体现出规模经济性。从区域上来看则是东部地区的能源效率最高,中部次之,西部最低。针对这一结果,本文给出几点建议：中西部地区应加强合作,发挥各自优势,开发新技术新能源,提高能源利用率,促进经济健康发展。

英文摘要：

Energy is the material basis for social development and it is closely related with economy. But now energy shortage, low utilization rate of energy and the deterioration of the environment have become the main restrictions of the economic development in China. Therefore, studying the energy efficiency has a practical significance for developing a harmonious and sustainable energy economy and building a conservation-minded and harmonious society. In this paper, firstly, based on the three-stage DEA model （DEA is an efficiency evaluation method based on the concept of relative efficiency which can be used to evaluate and sort decision-making units of the same kind）, we analyzed the energy efficiency of 29 provinces in china in 2009,set up an evaluation index system of energy efficiency to compare the differences of energy efficiency among regions and provide regions with theoretical guidance to adjust energy consumption strategy and improve energy efficiency; Secondly, we divided technical efficiency into pure technical efficiency and scale efficiency, analyzed the energy efficiency with its numerical value and added environment variables to perfect the results above; Finally, based on empirical research, we got the following three main results： 1） The scale efficiency is overestimated before eliminating external factors and environment variables while pure technical efficiency is underestimated. To solve the problems, the regions should expand the scale of the enterprises and pay more attention to energy efficiency; 2） The scale returns of most provinces in the third stage are increasing （except Shandong province）, which shows that many enterprises are too small to reflect the economy scale. Therefore, all regions except Shandong should increase their energy inputs to obtain the economy scale of energy utilization; 3） From the regional perspective, the eastern energy efficiency is the highest, then the central and the western is the lowest. According to the results, this paper offers some suggestio