In 1979, Prof. Ma Shijun proposed the eco-engineering principles of "integration, co-ordination, circulation, regeneration and revitalization". Specially, he pointed out that eco-engineering was a production-technology system by which co-existence of species and revitalization of matters were applied with the best possible methods of systematic engineering and multi-level circulation. In 1987, he further stated that agriculture built upon principles of eco-engineering was eco-agriculture itself. This paper substantiated the precision and foresight of Prof. Ma Shijun's theory with several successful models of eco-engineering: integration model of shelterbelt forest and farmland in oasis of desert region of Northwest China, mutualistic symbiosis model of rice-fish system, large scale circular economy model of livestock "breeding in the west and raising in the east" in northeast agro-pastoral transition zone of Inner Mongolia, and ecosystem component equilibrium model of high quality forage grass cultivation in low-yield farmland in Huanghuaihai grain-producing area. It also explained why eco-agriculture is an important part of modern eco-eco-civilization. Eco-agriculture consists of a series of eco-engineering projects based on the relevant ecological principles. This paper ended with several recommendations for speedy development of eco-agriculture in China.