| Quantitative information on the fraction of green vegetation is required in many studies of global and local change monitoring. The fraction of green vegetation, the ratio of vegetation occupying a unit area, is a very important parameter in development of climatic and ecological models. However, on-ground fieldwork surveys of the fraction of green vegetation are time consuming and expensive and produce low-precision results. Estimation of the fraction of green vegetation using remote senseing data may be a more efficient approach.In this paper, based on the FCD mapping model, the fraction of green vegetation in Beijing mountain area was calculated using the Landsat-TM data (with two digital images taken in 1994 and 1999, respectively). The landscape pattern of change on the fraction of green vegetation during this period was studied using a landscape pattern analysis program FRAGSTATS by analyzing path size, number of patches, shape metrics and landscape heterogeneity metrics to show the changing feature of landscape pattern. All of these results of indices analysis emphasize that the eco-environmental system in Beijing mountain area in a whole is stable and the fragmentation and heterogeneity level in the last five years is decreasing. But the temporal and spatial characteristics of change of landscape are different among different types of Beijing mountain area. In terms of different areas, the condition of vegetation cover in a whole has an increased trend in Changping district, Huairou county and Miyun county. However there is a bad trend in Pinggu county and Mentougou district, despite the fraction of green vegetation in the two districts is high. The spatial pattern analysis can help to identify the vegetation coverage spatial distribution and structure stability. So it is a very important factor for Beijing mountainous ecology system evaluation.
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