In　order　to　provide　more　grid　space　for　the　renewable　energy　power,　the　traditional　coal-fired　power　unit　should　be　operated　flexibility,　especially　achieved　the　deep　peak　shaving　capacity.　In　this　paper,　a　new　scheme　using　the　reheat　steam　extraction　is　proposed　to　further　reduce　the　load　far　below　50%　rated　power.　Two　flexible　operation　modes　of　increasing　power　output　mode　and　reducing　fuel　mode　are　proposed　in　heat　discharging　process.　A　600　MW　coal-fired　power　unit　with　50%　rated　power　is　chosen　as　the　research　model.　The　results　show　that　the　power　output　is　decreased　from　300.03　MW　to　210.07　MW　when　the　extracted　reheat　steam　flow　rate　is　270.70　t　center　dot　h(-1),　which　increases　the　deep　peak　shaving　capacity　by　15%　rated　power.　The　deep　peak　shaving　time　and　the　thermal　efficiency　are　7.63　h　center　dot　d(-1)　and　36.91%　respectively　for　the　increasing　power　output　mode,　and　they　are　7.24　h　center　dot　d(-1)　and　36.58%　respectively　for　the　reducing　fuel　mode.　The　increasing　power　output　mode　has　the　advantages　of　higher　deep　peak　shaving　time　and　the　thermal　efficiency,　which　is　recommended　as　the　preferred　scheme　for　the　flexible　operation　of　the　coal-fired　power　unit.