China　is　the　largest　primary　magnesium　producer　in　the　world,　because　of　nearly　80%　of　the　global　market　share.　In　the　present　paper,　an　approach　of　life　cycle　assessment　(LCA)　was　applied　to　build　an　inventory　of　air　emissions　and　to　analyze　the　environmental　impact　of　the　global　warming　potential　(GWP)　and　the　acidification　potential　(AP)　related　to　the　production　of　AZ91D　magnesium　alloy.　A　summary　of　environmental　impacts　of　primary　magnesium　and　primary　aluminum　production　with　various　studies　was　made　to　show　the　influence　of　uncertainties　on　the　impacts.　The　results　showed　that　the　cumulative　GWP　and　the　acidification　potential　(AP)　of　AZ91D　Mg-alloy　are　33.4　t　CO2　eq/t　ingot　and　139　kg　SO2　eq/t　ingot,　with　the　range　of　29.5-36.3　t　CO2　eq/t　ingot　and　104-152　kg　SO2　eq/t　ingot,　respectively.　The　GWP　and　AP　of　primary　magnesium　account　for　90%　and　77%　of　the　cumulative　environmental　impact　of　AZ91D　Mg-alloy.　Under　the　grand　background　of　advancing　the　development　strategy　of　energy-saving　and　emission-reducing,　China　magnesium　smelting　and　manufacture　industry　has　made　rapid　progress　in　the　structure　optimization,　energy　efficiency　improvement,　and　environment　protection.　The　calculated　data　show　that　the　improvement　measures,　e.g.　reduction　of　dolomite　consumption　and　energy　consumption,　in　Chinese　Pidgeon　process　led　to　23%　decrease　of　the　GWP　for　the　primary　magnesium　production　in　2009　compared　with　2005.　The　global　warming　reduction　potential　for　1　ton　AZ91D　alloy　ingots　produced　in　China　was　estimated　of　substituting　HFC-134a　for　SF6　as　a　cover　gas.