For　a　more　comprehensive　understanding　of　the　internal　flow　field　of　a　supercritical　carbon　dioxide　(SCO2)　compressor,　the　cavity　and　the　labyrinth　sealing　structure　are　designed　for　a　150　kW　simple　Brayton　cycle　SCO2　centrifugal　compressor　in　this　paper.　A　numerical　solution　of　the　three-dimensional　Reynolds-Averaged　Navier-Stokes　(RANS)　equation　and　k-Ε　(Extended　Wall　Function)　turbulence　model　was　used　to　study　the　aerodynamic　performance　and　axial　thrust　of　the　SCO2　centrifugal　compressor　considering　the　cavity　and　sealing　structure.　The　finite　element　method　is　used　to　analyze　the　stress　and　the　strain　characteristics　of　the　centrifugal　impeller　under　the　combined　effect　of　aerodynamic　force　and　centrifugal　force,　and　the　strain　of　the　designed　labyrinth　seal　is　also　calculated.　The　results　show　that　the　designed　aerodynamic　efficiency　of　the　SCO2　centrifugal　compressor　with　cavity　and　sealing　structure　is　72.1%　and　the　pressure　ratio　is　2.19　at　the　design　working　condition.　The　maximum　axial　thrust　of　SCO2　centrifugal　compressor　is　1　635　kN;　The　maximum　surface　equivalent　stress　of　centrifugal　impeller　is　109.95　MPa,　which　meets　the　strength　demand　for　304　steel.　The　leakage　flow　of　cavity　will　cause　the　reduction　of　aerodynamic　efficiency　of　SCO2　centrifugal　compressor,　but　under　the　high　flow　coefficient　condition,　the　cavity　leakage　can　alleviate　the　condensation　phenomenon　at　the　leading　edge　of　the　diffuser.　The　paper　provides　a　reference　for　the　analysis　of　the　aerodynamic　performance　and　strength　characteristics　of　the　SCO2　centrifugal　compressor　with　cavity　and　sealing　structure　as　well　as　the　design　of　the　sealing　structure.　©　2022,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.