The　new　configuration　of　a　transcritical　CO2　ejector　expansion　refrigeration　cycle　combined　with　a　dedicated　mechanical　subcooling　cycle　(EMS)　is　proposed.　Three　mass　ratios　of　R32/R1234ze(Z)　(0.4/0.6,　0.6/0.4,　and　0.8/0.2)　were　selected　as　the　refrigerants　of　the　mechanical　subcooling　cycle　(MS)　to　further　explore　the　possibility　of　improving　the　EMS　cycle＇s　performance.　The　thermodynamic　performances　of　the　new　cycle　were　evaluated　using　energetic　and　exergetic　methods　and　compared　with　those　of　the　transcritical　CO2　ejector　expansion　cycle　integrated　with　a　thermoelectric　subcooling　system　(ETS).　The　results　showed　that　the　proposed　cycle　presents　significant　advantages　over　the　ETS　cycle　in　terms　of　the　ejector　performance　and　the　system　energetic　and　exergetic　performances.　Taking　the　EMS　cycle　using　R32/R1234ze(Z)　(0.6/0.4)　as　the　MS　refrigerant　as　an　example,　the　improvements　in　the　coefficient　of　performance　and　system　exergy　efficiency　were　able　to　reach　up　to　10.27%　and　15.56%,　respectively,　at　an　environmental　temperature　of　35　°C　and　evaporation　temperature　of-5　°C.　Additionally,　the　advantages　of　the　EMS　cycle　were　more　pronounced　at　higher　environmental　temperatures.　©　2019　by　the　authors.