Abstract: The complex factors of the city ecosystem is influenced, restricted by each other and connected with each other. For improving the ecosystem, plants play a special role and cannot be replaced by any other thing. Along with the development of science and culture, more and more people have realized that making full use of plants has become the most important means of improving city ecosystem.From ancient times to the present, people’s viewpoints about landscape architecture have involved different stages, from mainly for excursion to for the sightseeing. Nowadays, the viewpoint has developed into the stage for improving city ecosystem, mixed excursion and the sightseeing togather with the well-rounded ecological environment.