A　thermodynamic　model　was　built　for　a　supercritical　carbon　dioxide　recompression　Brayton　cycle　with　main　compressor　intercooling　and　reheating　coal-fired　power　generation　system.　A　detailed　study　was　performed　to　investigate　the　effects　of　key　parameters　such　as　the　high　pressure　turbine　inlet　pressure,　high　pressure　turbine　inlet　temperature,　main　compressor　inlet　temperature　and　pressure　drop　ratio　on　the　optimum　thermal　efficiency.　Results　show　that　increasing　the　high　pressure　turbine　inlet　pressure　and　high　pressure　turbine　inlet　temperature　or　decreasing　main　compressor　inlet　temperature　are　conducive　to　the　increment　of　the　thermal　efficiency,　while　the　increasing　the　pressure　drop　ratio　can　increase　the　thermal　efficiency.　Finally,　a　comparison　study　was　performed　between　the　performances　of　the　supercritical　CO2　coal-fired　power　generation　system　and　a　practical　steam　coal-fired　power　generation　system.　The　results　show　that　the　SCO2　cycle　unit　can　obtain　the　comparable　or　lower　power　supply　coal　consumption　compared　with　a　steam　cycle　unit　by　improving　operation　parameters.　However,　the　SCO2　cycle　unit　has　a　larger　volumetric　flow　rate　of　working　fluid　in　the　boiler　compared　with　the　steam　cycle　unit　in　the　case　of　the　same　power　supply.　©　2018　Chin.　Soc.　for　Elec.　Eng.