This paper analyses the intrinsic relationship between ecology and city planning.The background and causes of the eco-city proposition are reviewed,and its intension is summarized into the following two words,harmony and development.The paper presents an opinion that the eco-city is not only the ideal mode of city for human,but also the succession climax of the urban ecological system.At last,the approaches of eco-city planning are discussed form the two levels of regional plan and master plan,which make a reference for the academic research and concrete practice of eco-city.