A　660　MW　unit　of　an　ultra-low　emission　coal-fired　power　plant　in　the　Beijing-Tianjin-Hebei　area　was　chosen　for　this　study.　The　particulate　matter　was　sampled　with　a　Dekati　low-pressure　impactor　(DPLI)　at　the　inlet　and　outlet　of　flue　gas　cleaning　devices　including　selective　catalytic　reduction　(SCR),　low-low　temperature　economizer　(LLTe),　electrostatic　precipitator　(ESP),　wet　flue　gas　desulfurization　(WFGD),　and　wet　electrostatic　precipitator　(WESP).　A　filter　sampling　system　was　also　used　at　the　inlet　and　outlet　of　the　WFGD　and　WESP.　The　removal　efficiencies　of　PM＜sub＞1＜/sub＞,　PM＜sub＞1-2.5＜/sub＞,　and　PM＜sub＞2.5-10＜/sub＞　from　different　flue　gas　cleaning　devices　were　obtained　after　ultra-low　emission　modification.　The　results　show　that　SCR　increases　the　mass　concentration　of　fine　particulates　and　PM＜sub＞1＜/sub＞　by　52.11%.　The　LLTe　improves　the　removal　efficiency　of　the　ESP,　especially　for　particles　with　a　range　of　0.1-1　μm.　The　high-efficiency　WFGD　removes　both　SO＜sub＞2＜/sub＞　and　particulates,　but　it　increases　PM＜sub＞1＜/sub＞.　The　mass　concentration　of　PM＜sub＞1＜/sub＞　increases　by　59.41%　and　the　water-soluble　Mg＜sup＞2+＜/sup＞,　Cl＜sup＞-＜/sup＞,　and　SO＜sub＞4＜/sub＞＜sup＞2-＜/sup＞　in　PM＜sub＞10＜/sub＞　increases.　The　WESP　has　a　high　removal　efficiency　with　respect　to　PM＜sub＞1＜/sub＞,　PM＜sub＞1-2.5＜/sub＞,　and　PM＜sub＞2.5-10＜/sub＞　and　can　further　reduce　the　dust　concentration.　Based　on　an　ultra-low　emission　reform,　the　final　PM＜sub＞10＜/sub＞　emission　of　this　660　MW　unit　is　2.04　mg·m＜sup＞-3＜/sup＞.