Abstract: Since reform and opening，China's economic has developed rapidly and social progress is obvious. It is a positive change from the interaction among the society，economy and ecology. Their interaction can provide the necessary basis for the coordination of the relationship between the implementation of ecological compensation， environmental change and macro-control studies. Since implementing the strategy for development of the western region of China in 2001，the development focus has changed from the eastern coastal areas to central and western inland regions. The west area of China is an ecologically fragile and economically underdeveloped area. And it is the special area of the country's overall ecological security，economic security，which is a comprehensive，coordinated and sustainable development region. Because researching the coupling relationship between economy，society and ecology of western region based on time and space is necessary，this paper chooses the western region as the research area. Based on the statistical data of western region in 1990，1995，2000，2005 and 2010，this paper used the analytic hierarchy process（AHP）to establish the index system between economy，society and ecology of the western region，and analysis evaluation in the western typical region. Economic system includes economies of scale，economic structure and economic efficiency. The social system consists of four places，scientific and technological progress，infrastructure， living standards and urbanization. Ecosystems include water resources，land resources，climatic conditions，biological resources and ecological pressure. And a dynamic coupling model was built for monitoring the coupling relationship between economy，society and ecology. The coupling coordination level was used to measure the degree of coordinate development between the three systems. The statistical data come from China statistical yearbook.  In 1997 Chongqing was promoted to build one of municipalities，so the statistical data of Chongqing in 1990 and 1995 refer to data of Chongqing from Sichuan Province statistical yearbook data，the data of Sichuan Province exclude the dada of Chongqing. In order to eliminate the impacts of differences in the dimension on the indicators，two types of  positive and negative indicators were set up with a dimensionless handling. The results show as follows：（1）In nearly 20 years，the economy in western regions sustained rapid growth. And economic level develop obviously in the regions east of Gansu Province. Economic development improved living standards and remained relatively parallel compare with social progress. The ecological level was significantly higher and its fluctuation was smaller in southwest region than that of northwest area. Ecology was improved from 1995 to 2000 and had a deterioration trend after 2000. （2） Interactive trend of society and economy systems’ development modes was obvious，and comparing with economic development，the society progress had a short lag. （3）The coupling coordination level was growing between the three systems. It was revealed that the relationships between the various systems have a trend to present a coordinated development with the passage of time. But the change of economy-ecology coordination degree was not obvious and some areas had declined trend from 2005 to 2010. Degradation of ecological level causes the stagnant growth of coordination degree.

Key words: Western China, economy-society and ecology, coordinated development