The degraded ecosystem in the Loess Plateau region of China is very vulnerable, which has a great impact on regional sustainable development. Taking the Loess Plateau of Yan’an, Shaanxi province, China, as the study area, this study quantitatively evaluated conditions of the ecological environment. Based on natural factors, environmental factors, and socio-economic factors of Yan’an in 1997, 2004, and 2011, the dynamic changes in ecological vulnerability are analyzed with the application software for geographic information systems (GIS). The analytic hierarchy process (AHP) model was used and it contains variables for land use, soil erosion, topography, climate, vegetation, and socio-economic data. The evaluation results are divided into fi ve categories: potential, slight, light, medium, and heavy. The results show that the ecological vulnerability in the study is light level, and the ecological vulnerability index of the southern four counties is lower than that of the northern four counties. Ecological environment quality gradually improved in most areas in 1997~2011.