Abstract:As one of the most serious natural disasters, earthquake normally brings huge ecosystem damage. But the quantitative assessment to this kind of ecosystem damage is relevant difficult. This paper studied the ecological characteristics of the earthquake losses in western China. After analysing the recent research of earthquake-caused ecosysteml losses assessment, an ecosystem loss assessment model for the western China earthquake is proposed in this paper:Eq=ED+ERC+ERL ，Index analysis and the opportunity cost method are used to build up the basic theory and calculation model of the earthquake study. A method of combining the earthquake ecological loss and the disaster degree of the earthquake ecological damage is proposed for the purpose of earthquake ecological damage estimation in certain regions. By using this model, the forest carbon reserve capacity in Sichuan Province gets an annual loss of 781,000t after the earthquake, which counts for the value loss up to 2.5×108 yuan, while the capability of forests releasing oxygen reduces 673,800t annually, with the value loss of 2.7×108 yuan. Direct ecosystem loss (ED) is 647.58×108 yuan, while ecosystem restoration cost (ERC) is 1158.31×108 yuan. The provincial forest ecological service value losses amounts to 1055.88×108 yuan. The integrated ecological damage is 3527.31×108 yuan, with the disaster degree being 0.38, sorted to the obvious disaster damage. The rapid assessment of the disaster losses and the disaster degree have important positive impact to guide post-disaster ecosystem reconstruction and ecological disaster prevention.