Abstract: Eco-efficiency, as it takes into account both economic and environmental benefits, is a core indicator of quantitative description of relationships between environment and economic systems and a hotspot as well in appraising development of eco-industrial parks (EIP). Based on the theories of ecological footprint and eco-efficiency and the ecological footprint accounting methods available, a mathematic model was established for evaluating eco-efficiency of EIP and used to evaluatione eco-efficiency of the Kunshan EIP. Results show that eco-efficiency of the Kunshan EIP has been improving slowly year by year and its main limiting factors are the demands of the practitioners in the park for biological resources and the poor eco-efficiencies of the electronic information industry and the other industries except for the three leading industries.