Abstract: The forest ecosystem in the upper Yangtze River basin is a significant ecological shelter belt.Taking the upper Yangtze River as a study area,this paper adopted RS and GIS techniques to evaluate the stability of forest ecosystem in a large scale and made a deep analysis of its spatial distribution characteristics by establishing"disturbance-response"(D-R) framework and index system of stability evaluation of forest ecosystem.The results showed that:(1)The stability of forest ecosystem of study area was overall below the average.The mild stable,unstable and very unstable regions accounted for 50.09% of the whole area,of which 6.63% was very unstable,19.29% was unstable,24.17% was mild stable,26.29%was moderate stable,and 23.62% was stable.(2)Its spatial distribution pattern showed that the forest ecosystem stability was better in northwest region while worse in southeast,and there was a positive correlation between the stability and the altitude.Areas of poor stability were mainly distributed on the slopes of 10°-25°,and areas distributed on the slope over 25°were in better stability.The research could provide not only a scientific basis for the conservation and restoration of forest ecosystem in the upper Yangtze River,but also important policy-making reference for eco-environment protection and ecological barrier construction in the study area.

Key words: upper Yangtze River, forest ecosystem, stability evaluation, spatial differential features