A city is an open Complex Adaptive System CAS) in which interrelated sub-systems integrate into an organism with functions of learning, self-adapting and self-organizing. This article analyzes urban self-organization system firstly. Population, energy, capital, information and other factors flowing in space constantly and producing a new order by differentiation and integration, constituting the open, away from the balance of urban system, nonlinear function and fluctuation etc. self-organization elements and conditions, is a city with typical dissipative structure characteristics. The evolution of urban systems with dissipative structure has the self-organization growth characteristics from the bottom-up. And then the paper focuses on analyzing the force driving self-organization evolution of city system——competition and cooperation on——both regional and city scales, and at the same time carries out the empirical analysis. Competition and coordination is ubiquitous in the city system. They exist in three different levels of urban space system development. Firstly, developers stay competitive for advantage position, and create development poles and growing point to form the spatial agglomeration in the regional system. Secondly, many of city or community competition in space field and formation hinterland, market and the affected zone, expand the urban space form step by step. Thirdly, spatial form has been formed due to the evolution and development of urban systems, and to promote the new competition, resulting in succession and update of space function and nature. City is in such a mechanism of evolution exactly. Benign competition collaborative competition) is beneficial to developing city system, and promoting the urban sustainable development; On the other hand, the excessive competition or lack of power will lead to disorder, obstruct the development of the city.