With　the　increase　of　the　proportion　of　non-fossil　fuels　in　power　generation,　coal-fired　units　play　an　important　role　in　load　cycling　of　power　grid　more　and　more　frequently,　leading　to　off-design　operation　conditions　for　a　long　time.　In　this　study,　the　pollutant　emission　inventory　of　a　1000　MW　ultra-supercritical　coal-fired　unit　is　calculated,　and　its　influence　on　the　environment　is　discussed.　The　results　show　that　the　Photochemical　ozone　creation　potential　and　global　warming　potential　are　dominant　factors　which　have　a　contribution　of　about　82%　in　the　total　environmental　impact　potential.　With　the　decrease　of　load　from　BMCR　to　40%THA,　the　total　environmental　impact　potential　increases　gradually,　indicating　an　increasing　influence　of　the　power　plant　on　the　environment.　This　is　mainly　because　of　the　increase　in　the　amount　of　coal　used　in　1kWh　power,　and　the　denitrification　efficiency　decreases　sharply　under　low　loads.　The　total　environmental　impact　potential　under　40%THA　load　is　about　34%　larger　than　that　under　BMCR　load.　©　2019,　Science　Press.　All　right　reserved.