Abstract: China has witnessed great advances in ecological engineering in the past decade. The objective of the study has expanded to cover the entire social economic and natural complex ecosystem,oriented for sustainable development ,benefit to both human society and nature,harmonized development of the economy and the environment ,and shift from the one dimensional pursuit of economic growth or environment and nature conservation to a three dimensional one of prosperity of a three in one complex ecology comprising wealth(growth and accumulation of both economic and ecological assets),health(physical and intellectual integrity of the people and sound service function and metabolism of the ecosystem)and culture(material,spiritual and ecological civilization). Based on the four consummated rationales of integrity(of time,space and function),harmony(symbiosis and co evolution), recycling (material and information feedback)and spontaneity(competition and self regulation),and eco cybernetics,eight principles for ecological engineering designing have been derived. Its methodology has developed from physical quantification to ecological seriation,from optimization of engineering structure to evolution of ecological patterns,and from mechanical artificial intelligence to human ecological intelligence.Its technical route has been developed to include coupling of hardware,software and mindware,combination of multi disciplinary and multi technological systems ,regulation of the entire ecological course of the compound ecosystem,expression of environment protection in production and consumption and of waste disposal in utilization,and vertical and horizontal coupling of structure with function into food chain network,life cyclenetwork and ecosystem network. Moreover,its application scope has been expanding to a variety of fields.

Key words: ecological engineering, eco industry, eco technology, environment protection, sustainable development