Abstract：Since1990s, it has become an international trend to pay more attention to the harmony between residence environment and nature. The concept of “landscape city” was put forward, corresponding to ancient Chinese’ idea of construction. In ancient China, the outlook on nature of our forefathers experienced from the adoration for life to value the perceptual life, then deducing a kind of life spirit to be the essence of the cosmos in philosophy. The respect to life conceives the traditional ecology-thought of China. As early as from the Spring-autumn Period to the Warring States Period, the traditional ecological wisdom of China has already followed the mature stage, and the more perfect ecological ethics and natural aesthetic have already taken shape basically. The culture of "Rite(li) and Art(yue)" based on the traditional ecology is an important means to integrate the relations between nature and man. It pursues the harmony between nature, man and ecology, with life spirit.

Cities carried human’s civilization. The philosophy of existence，the creation of art and culture are reflected in the construction and development of the city. With the blend of the traditional philosophy on the unity of nature and man, the classic garden arts and the city construction mutually, it has evolved a special garden city of landscape in ancient China. In practice, a pattern comes into being in site-selection and planning etc., expressing the concern for the ecosystem, aesthetic and the person's emotion. Based on practices on city construction, the way of city construction in "Rite of Zhou " (Zhou Li )have already been systematized, which lay a solid foundation for all the later cities, especially for the capital cities. The basic idea on city construction is to build up cities on the base of ecology including the resources to be used continuously and environment development to be kept, in order to making a poetry environment which is harmony between man and nature and suitable for dwelling. After practices and developments of the past dynasties, the city of Beijing in Qing Dynasty has reached a perfect state.

The paper takes the ancient capital city of Beijing as a typical example. It analyses the influence of the Beijing river system on the city structure in different dynasties of Jin, Yuan, Ming and Qing. Meanwhile, the river system of cities is the key to the site-selection and construction of city gardens, especially of the large-scale imperial garden. The paper therefore gives a detailed analysis for the imperial gardens construction of the WesternGarden (Xiyuan), the Southern Garden ( Nanyuan ) and the northwest gardens which play an important role in urban landscape, climate and ecosystem and so on. In addition, with the influence of the garden culture led by imperial gardens, various gardens spread all over the capital city. Even the small courtyards of Beijing citizens’ residence were made green highly. Thus, it draws the conclusion that Beijing has already become an ecological landscape city.

Keywords: Landscape city; Garden; Life spirit; Ecological culture