The　isentropic　exponent　in　the　near-critical　region　can　sharply　change　with　operation　condition　transitions　of　a　closed　Brayton　cycle,　thus　having　significant　impacts　on　the　compressor　aerodynamic　performance　and　the　internal　flow　of　the　compressor　embedded　into　the　cycle.　This　paper　investigates　the　isentropic　exponent　effects　of　the　supercritical　carbon　dioxide　(CO2)　using　theoretical　analyses　and　three-dimensional　computational　fluid　dynamic　(CFD)　simulations.　The　theoretical　analysis　reveals　that　the　increasing　isentropic　exponent　mitigates　the　impeller　work　coefficient　and　the　impeller　outlet　Mach　number　but　raises　the　suction　side　Mach　number　of　the　impeller　blade　and　blade　loading　at　the　leading　edge.　The　CFD　results　provide　validations　for　the　theoretical　results.　Based　on　the　findings,　a　suggestion　is　offered　to　guide　the　physical　experiment　design　of　a　centrifugal　compressor　with　supercritical　CO2　as　its　working　fluid.　©　2022　Ben　Zhao　and　Zhiyuan　Liu.