A　theoretical　model　of　the　transcritical　refrigeration　cycle　with　natural　refrigerant　N2O　was　established,　and　the　performance　of　the　transcritical　compression/ejection　cycle　and　the　simple　transcritical　cycle　with　N2O　was　compared　with　that　with　CO2.　The　results　show　that　the　coefficient　of　performance　CCOPof　the　N2O　system　increases　by　13%　for　the　transcritical　compression/ejection　cycle　and　by　9%　for　the　simple　transcritical　cycle　compared　with　that　of　the　CO2system.　However,　the　discharge　pressure　decreases　by　16%　and　13%,　respectively.　Moreover,　the　CCOPof　the　CO2system　increases　by　15.2%　when　adding　an　ejector　while　the　CCOPof　the　N2O　system　increases　by　11.6%,　compared　with　that　of　the　simple　transcritical　cycle.　The　influence　of　the　high　side　discharge　pressure,　evaporation　temperature　and　gas　cooler　outlet　temperature　on　the　performance　of　the　transcritical　compression/ejection　cycle　with　N2O　or　CO2was　also　analyzed.　The　results　indicate　that　the　variation　trends　of　the　CO2system　and　the　N2O　system　are　similar,　and　the　CCOPof　the　N2O　system　increases　more　obviously　than　that　of　the　CO2system　when　the　gas　cooler　outlet　temperature　is　lower　or　the　evaporation　temperature　is　higher.　The　analysis　on　the　thermal　stability　of　N2O　shows　that　N2O　has　good　thermal　stability　and　will　not　be　decomposed　in　the　transcritical　refrigeration　cycle.