Abstract: The world's forest vegetation has been playing an active role in the process of geosphere and biosphere.It is the“sink”of matters and the“pool”of certain energy accumulation in the process of material circulation and energy transfer in the near-earth atmosphere,meanwhile it is also the“source”of some other materials and certain energy release.Furthermore,it is the important passage for material circulation and energy transfer of bioproduction stocks and the atmosphere-vegetation-soil system.The global forest ecosystem is regarded as the most diversified terrestrail ecosystem,adapted to the wide range of climatical zones,from frigid to tropic with various tree and shrub species as its main components.Forest ecosystem is a terrestrail ecosystem of most complicated time-space structure with large capacity of feed-back and self-organization,i.e.larger elasticity and stability.This system possesses the most enormous biomass and biological productivity among all the terresterial ecosystems, which is the principal part of the land photosynthesis production.Owing to its complicated passages for mass circulation and energy transfer,the system itself can maintain the systemstability and biological productivity,which plays an important roie in biogeochemical circulation of biogeosphere.So far,the research on the structure and function of forest ecosystem is still of the first tasks in respect of relationship between global changes and world forest ecosystem.