Abstract: City is composite system of artificial system and natural system. There are interacts and effects within and between the cities[JP8]’e[JP]conomy, ecology, environment, society, culture, institution and other systems. The city is complex and diverse system with its external relations.The city is an open, complex giant system. Operation of urban systems requires a high organization level.Urban system with the complexity and ambiguity features. Using the simple, intuitive, static methods to study and evaluate development quality of urban system, their conclusions will be lost for practice. Therefore, using system, fuzzy, dynamic approach to evaluate and analyze urban systems is necessary based on system science and fuzzy system theory. This paper builds an evaluation index system for evaluating the urban economy, environment and society development based on principle and method of the built index system, and uses the evaluation method and model with the help of the fuzzy classification dealing with the coordinated degree, coordinated development degree and coordinated development trend to evaluate the coordinated development of economy, environment and society of the five capital cities of northwest China. Firstly, to sort out the status of evaluation research about the coordinated development of economy and environment of region. Secondly, to establish the evaluation index system about coordinately developing economy, environment and society of the cities, and lead into and improve the model on evaluation of fuzzy classification. Thirdly, to evaluate and analyze the coordinated development state about economy, environment and society of the five capital cities of northwest China from 2003 to 2009. At the end, to come to the conclusions. A comprehensive evaluation of five cities is low in 2005 and 2009. Economy system and comprehensive evaluation of complex systems of five cities is low in 2005 because economic indicators of five cities are lower or unchanged than the standard index value. The society system and comprehensive evaluation complex system of five cities are low in 2009 because the various indicators of society system of five cities are large floating relative to the standard value. Level of economy system and society system are low in Xi’an. Society system is decay trend in Xi’an. Lanzhou’s economy, environment and society system development level is low. Xining’s economy development system is the worst among five cities and society system is decline trend. Urumqi’s economy development system is best among five cities, but Urumqi’s society system development is recession. Environment system development of Yinchuan is the best among five cities and the development of economy system is after Urumqi. The overall development level on economy, environment and society is not high in five northwest cities, and there are differences in the coordinated development on economy system, environment system of cities .So it affects the overall coordinated development level of the five cities. Yinchuan’s overall development is the best among five cities, followed by Urumqi, Xi’an, Lanzhou, and Xining’s development is the worst. It should be noted that the social system of Xi’an, Xining and Urumqi are declining trend. Innovation of this paper is as follows: Building evaluation system on urban economy, environment and society development. Improving and refining the fuzzy hierarchical evaluation model. Leading into coordinated degree, coordinated development degree and coordinated development trend in coordinated development of urban evaluation index systems.

Key words: fuzzy classification evaluation, city, coordinated development, fuzzy system