Abstract: 【Objective】In order to quantitatively evaluate the dynamic changes of ecological vulnerability in Miyun County of Beijing City.【Method】By using remote sensing(RS)and geographic information system(GIS)technology to preprocess 12 kinds of grid data from two aspects of natural environment and social data, a spatial database for the ecological environment quality evaluation index with a spatial resolution of 30 m was established. Based on the sensitivity-elasticity-pressure model, a multi-level fuzzy comprehensive method coupled with a natural boundary method was used to assess the ecological environment vulnerability of Miyun County through dividing the vulnerability into five grades. Further, the spatio temporal variations of vulnerability were analyzed based on transfer matrix method, followed by a validation using vegetation coverage data collected from filed investigation. 【Result】For ecological environment quality in 2003-2013, the northern mountainous area was better than that of the southern plains, and forest region with a higher altitude was better than that of the low altitude farming area. The area proportion of moderate vulnerable area in the study region in 2003 was the largest, followed by the slight vulnerable area, with an area ratio of 40.43% and 37.00%, respectively. The sum of area percentage of slight vulnerable area and low vulnerable area in the study region reached 76.52% in 2013, absolutely showing a dominance of improvement trend. 【Conclusion】After a 10-year’s construction of a series of ecological and environmental protection projects such as natural forest protection project, as well as implementation of environmental protection policy, the ecological environment quality of Miyun County has been greatly improved. The evaluate method based on the sensitivity-elasticity-pressure model could be applied to evaluate the ecological vulnerability at Province, District and County scale.