The paper presents a quantitative approach for Green Buildings assessment in new city, Korea. This study is analyzed energy consumption and carbon dioxide emissions in buildings in Geom Dan new town district 1, and then estimated carbon dioxide emission abatement potential from sustainable and high performance building strategies which determines the possibility of achieving the nation’s green house gas reduction goal. It is provided environmentally conscious guideline for Korea's urban development model transforming into “Low Carbon Eco-City” in the early stages of city planning.