As the emissions of greenhouse gases have led to changes in the global climate, more and more concerns have been on the issues of energy use and emission performance. It is hence necessary to regularly and systematically measure and monitor the environmental performances for countries worldwide. Both the environmental data envelopment analysis (DEA) technology and environmental slack-based model (SBM) are used in this study to evaluate the efficiency scores of APEC economies for the period of years 2006 to 2010. The environmental DEA model is to evaluate the energy use efficiency and carbon reduction efficiency scores in the first stage, while in the second we establish an environmental-economic efficiency (EEE) index and a regression model to explore the key environmental variables affecting the EEE value. Preliminary results show that most APEC economies performed better in energy use efficiency than in carbon reduction efficiency. Apart from that, most APEC economies have resulted in better economic efficiency than in environmental efficiency.