From　October　5-13,　2014,　eastern　China　experienced　a　severe　air　pollution　and　haze　event,　which　affected　unusually　sizeable　areas　and　lasted　for　a　long　period.　In　order　to　better　understand　the　characteristics　of　the　episode　and　to　study　its　meteorological　reasons　and　formation　processes,　this　paper　performs　statistical　analyses　of　temporal-spatial　distribution　of　the　air　pollution　using　AQI　(Air　Quality　Index)　data.　The　present　study　employed　NCEP　(National　Centers　for　Environmental　Prediction)　reanalysis　and　meteorological　data　from　the　surface　and　high-balloon　stations　to　analyze　the　main　system　patterns,　weather　conditions　and　wind　fields　in　the　PBL　(planetary　boundary　layer)　and　the　upper　air　during　the　episode.　The　results　showed　that:　1)　the　North　China　Plain　and　the　Northeast　China　Plain　were　the　most　polluted　areas　in　this　episode.　Lasting　pollution　in　each　city　was　the　main　characteristic　of　the　episode.　The　time　variation　of　the　heavy　air　pollution　process　could　be　divided　into　three　stages,　including　AQI　ascent,　lasting　pollution　and　AQI　descent.　2)　During　the　AQI　ascent　stage　(October　6-8),　the　anticyclone　in　eastern　China　showed　a　local　and　a　south　weak　wind　field　at　the　surface　and　strong　temperature　inversion　at　3000　m,　which　are　favorable　for　pollution　accumulation.　The　weather　conditions　provided　valuable　interpretation　for　dramatic　AQI　ascent.　3)　During　the　lasting　pollution　stage　(October　8-11),　the　stagnation　of　the　anticyclone　over　the　sea　and　typhoon　“Yongfong”　gave　rise　to　lasting　eastern　and　southern　winds　in　the　East　China　Plain　for　four　days,　which　were　important　factors　in　the　lasting　pollution　episode.　4)　The　front　of　the　follow-up　anticyclone　(October　11-12)　was　favorable　for　pollution　removal,　which　was　the　main　system　pattern　for　the　AQI　descent.　In　conclusion,　the　lasting　stable　system　pattern　was　the　main　meteorological　reason　for　this　episode.　©,　2015,　Editorial　department　of　Molecular　Catalysis.　All　right　reserved.