Abstract: Ecological environment degradation,which is affected by natural condition and human activity,is very universal in the west region of Inner Mongolia.According to the degree of land use change,environmental degradation and human activity excretion in county(banner or city) unit,we chose seventeen major factors that obviously influenced the environment as the evaluating indices to assess ecological environment by using methods of comprehensive index and gray correlation index.Results showed that the indices of ecological environment quality varied from -28.35 to 2.67 in this region.The quality of ecological environment based on evaluation results in county(banner or city) unit was divided into four levels.First level,county(banner or city) occupied 15.4% among of total counties,second 36.5%,third 34.6% and fourth 13.5%.The results also showed that there should be good status of ecological environment if major activity is grazing in some county(Banner).On the contrary,urban area was surrounded by degraded environment.The quality of ecological environment is moderate in rain and irrigation agriculture areas.

Key words: west region of Inner Mongolia, ecological environment, comprehensive evaluation