In　this　study,　A　multi-layer　nested　model　was　developed　by　coupling　the　meso-scale　meteorological　model　ARPS　and　the　air　quality　model　CMAQ.　The　contributions　from　the　construction　fugitive　dust　effect　on　the　air　quality　of　Beijing　were　investigated　using　this　model.　The　data　of　January,　April,　August　and　October　in　2002　were　used.　Results　suggest　that　average　construction　contribution　of　the　four　months　is　8.82%,　8.25%.,　12.14　%　and　13.74%,　respectively.　The　construction　fugitive　dust　emissions　control　were　quite　poor　before　2004.　A　new　project　was　put　forward　by　the　regulatory　authority,　and　a　projected　reduction　of　52.3%　of　the　emissions　from　the　year　2002　was　given.　According　to　the　new　simulations,　the　decrease　of　the　emissions　by　the　new　scheme　can　improve　the　air　quality　of　Beijing.