Polygeneration system for chemical and power has been regarded as one of promising technologies to use fossil fuel more efficiently and cleanly. A new optimization method for polygeneration system integration has been proposed in this paper. Element utilization and energy utilization were presented as objective functions simultaneously, parameter variations and technology conditions were performed to investigate the influence of each unit specific operation conditions on the performance of the system by Aspen Plus 2006. The treatment of multi-objective values selection is discussed as well. The new optimization method proves to be effective to solve multi-objective optimization problems. It not only shows technologies and operating conditions needed to be improved obviously but also provides detailed changes of each unit performance during optimization process. With 62.3% energy efficiency, 64.8% element conversion efficiency and 56.6% CO2 + CH4 conversion efficiency, the optimized system shows a better performance in considering of the thermodynamic characteristics, element conversion and environment. And CH4/CO2 reforming process is found to be the key to element conversion and greenhouse gas emissions reduction. (C) 2011 Elsevier Ltd. All rights reserved.