Sustainable buildings with low environmental impact have attracted great social concern. The purpose of this study is to evaluate the environmental impact of a sustainable building which utilizes local timbers and energy-saving systems quantitatively with life cycle assessment (LCA) method. In this study, the database for LCA is developed based on field survey. This paper describes the out line of the environmental impact assessment of government offce with low environmental impact based on the performance values. The effect of environmental burden reduction is evaluated quantitatively with Life-Cycle Impact assessment Method of Endpoint modeling (LIME).