The　dioxins　(DXN)　are　a　set　of　pollutants　encompass　polychlorinated　dibenzo-p-dioxin/dibenzofuran　(PCDD/F),　their　emissions　from　municipal　waste　incineration　processes　(MSWI)　are　normally　detected　under　steady　oper-ating　conditions.　However,　limited　studies　have　focused　on　the　PCDD/F　emission　characteristics　under　a　com-plete　maintenance　operating　period　(CMOP),　which　includes　shut-down,　cooling,　maintenance,　heating,　startup,　and　normal　operations.　In　this　article,　the　shutdown　process　(SDP)　starts　from　the　normal　operation,　followed　by　shutdown,　and　then　cooling;　while　the　startup　process　(SUP)　commences　from　heating,　followed　by　startup,　and　then　normal　operation.　The　detection　and　analysis　were　conducted　at　the　SDP　and　SUP　stages.　The　PCDD/F　mass　and　total　toxic　equivalent　quantity　(TEQ)　concentrations　were　measured　in　the　flue　gas　and　bag　filter　fly　ash　(BF-FA)　during　a　CMOP　of　Beijing　MSWI　plant.　The　highest　PCDD/F　concentrations　in　the　flue　gas　were　found　in　the　＂cooling＂　and　＂startup＂　phases;　in　the　FA,　this　condition　occurred　in　the　＂startup＂　phase.　Further,　the　results　show　that　the　most　heightened　concentrations　were　observed　for　5-6　chlorinated　PCDF　and　4-5　chlorinated　PCDD　among　the　17　PCDD/F　congeners　in　most　cases.　More　importantly,　the　air　pollution　control　devices　(APCDs)　which　include　activated　carbon,　lime,　and　BF,　have　high　removal　efficiency　for　PCDD/F　(especially　PCDD)　during　the　＂startup＂　phase.　APCDs　also　easily　release　a　considerable　amount　of　PCDD/F　because　of　the　memory　effect,　which　emits　more　PCDD/F　at　the　＂shutdown＂　phase　than　at　the　＂startup＂　one.　Besides,　the　annual　PCDD/F　emission　in　the　flue　gas　of　the　MSWI　plant　was　estimated　to　be　67.72　mg　I-TEQ,　of　which　the　emission　accounts　for　approx.　20%　during　the　CMOP.　Moreover,　the　experiment　shows　that　the　PCDD/F　emissions　of　the　MSWI　plant　in　Beijing　under　unsteady　conditions　are　more　miniature　than　those　reported　earlier　in　other　areas.