In　order　to　analyze　the　characteristic　of　PM2.5　concentrations　and　assess　the　effect　of　the　temporary　control　measures　during　the　APEC　meeting,　the　variation　of　PM2.5　concentration　and　its　components　before-,　during-　and　after-APEC　were　analyzed　and　the　role　of　meteorological　conditions　and　pollution　control　measures　to　the　improvement　of　air　quality　were　explored.　Then　CAMx-PSAT　model　was　used　to　quantitatively　analyze　the　effect　of　improving　the　air　quality　of　the　pollution　control　measures　for　different　sources　in　different　regions.　Different　scenarios　were　defined　to　compare　the　situations　between　the　control　measures　implemented　or　not　during　the　APEC　meeting.　The　results　showed　that　the　average　daily　PM2.5　concentration　in　Beijing　during　the　APEC　was　lower　than　the　National　Environmental　Standard　(75μg/m3),　PM2.5　pollutants　were　mainly　emitted　from　the　local　emission　sources,　of　which　vehicle　exhaust　was　the　main　pollution　source,　accounting　for　36.1%.　PM2.5　concentrations　in　Beijing　decreased　by　43.0%　because　of　the　implementation　of　the　temporary　control　measures　during　the　APEC　meeting.　The　stringent　control　measures　implemented　in　Beijing　and　its　surrounding　areas　dominantly　contributed　for　＇APEC　blue＇.　©　2016,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.