Rapid urbanization stimulates the consumption of resources and the damages on ambient environment. The consideration of environmental protection and resource conservation must be involved in urban planning procedures. Actually more and more planners have realized this problem and started to apply ecological theories and methods in urban planning. The practice of urban planning combining with ecology was demonstrated, using Chengnan New District of Jintan City as the case study. In this case study, environmental impact assessment of the plan was simultaneously carried out so that the remarks of environmental impact assessment could be fed back to the planning procedure. Ecological principles and standards were set up as the ecological deadline of the city development.