By taking the Yuzhong area as an example,thematic raster layers of each evaluation factor are established based on DEM,survey data, remote sensing images,and 3S technologies.From the humanistic and natural point of view,vigor,organization,load,resilience,ecosystems maintenance,external input,and human health are chosen as the assessing elements based on the method of AHP.T he assessing result is classified into five classes: very healthy state,healthy state,sub healthy state,nor-healthy state,and morbidity state. In the end, the following conclusion is drawn: the area of nor-healthy state makes up 40>-50> of Yuzhong County,which indicates that the ecosystem healthy state declined from 1991 to 2006.