Application of urban ecosystem diagnosis into plan environment impact assessment

With the rapid development of economy and urbanization, urban environment is getting increasingly worse, several cities even face serious ecological crisis. So that carrying out the application of urban ecosystem research into cites´ sustainable development decision-making is becoming the key task to solve the contradiction between environment protection and urban economic-social development. Since the implementation of the EIA law, plan environmental impact assessment (PEIA) has been widely used and becomes a powerful tool of scientific decision-making. However, a lack of technical approaches constrains PEIA´s applications. So in order to ensure urban ecosystem coordination, complete the methodology framework of PEIA and improve the application level, using the system theory and ecological principles, the paper proposed an approach of urban ecosystem diagnosis which can be applied in PEIA. The urban ecosystem symptoms were listed systematically through status-analysis, the causes were identified by reviewing, and the trends were predicted by stress analysis, after the comprehensive analysis of the symptoms causes and trends, it eventually put forward suggestions on urban sustainable development. And the PEIA of the 11th Five-year Plan for Urban Economic and Social Development of Linfen city was took as a case of specific application in PEIA of urban ecosystem diagnosis.