In　order　to　reduce　the　carbon　emission　from　buildings　effectively　and　choice　the　technique　of　construction　waste　disposal　and　resource　appropriately,　a　calculation　method　of　building　carbon　emission　was　built　on　the　basis　of　life　cycle　theory,　and　the　carbon　emissions　of　two　public　buildings　in　Beijing　were　quantitatively　calculated.　The　results　show　that　the　carbon　emission　at　their　using　phase　accounts　for　82%　and　89%　respectively,　and　carbon　emission　at　the　building　material　production　phase　is　17.3%　and　10.4%　respectively　during　the　50　years　of　life　cycle.　Then,　according　to　the　optimization　of　energy　structure　and　green　building　energy-saving　requirements　in　Beijing,　the　carbon　emission　reduction　was　calculated　based　on　the　scenario　analysis,　and　the　policy　suggestions　for　reducing　the　carbon　emission　in　public　building　areas　were　put　forward.　At　last,　the　different　scenarios　of　the　construction　waste　disposal　and　recycling　were　analyzed　and　carbon　emission　at　different　scenarios　was　quantitatively　calculated　according　to　the　current　conditions　of　waste　disposal　in　China.　©　2016,　Beijing　University　of　Technology.　All　right　reserved.