In the period of the city space expanding with the high speed, the theories system used to explain the city space is not perfect in our country. It is lack to expand this mechanism, among them research ecosystem' s main factors to particularly should be enhanced, especially the ecological factor. With rational analysis, the paper puts forward the viewpoint that the urban space is in ecological changing period, and considers that the power affecting the urban space expand involves motivity and resistance. Building the corresponding ecological model helps to cognize the city development roundly with ecological model constructed. A few possible ways is put forward which can be used in planning innovation, and have vivid leading function to the frondose city planning method.