R290,　as　an　effective　and　environmentally　friendly　refrigerant,　has　great　potentials　in　the　application　of　air-conditioning.　In　this　paper,　the　performance　of　inverter　air　conditioner　(AC)　using　R290　was　compared　theoretically　with　that　of　other　refrigerants.　Moreover,　the　performance　of　a　split　AC　was　experimentally　studied　in　both　summer　and　winter　conditions　with　different　ambient　temperatures.　Results　show　that　the　performance　of　R290　AC　system　is　theoretically　higher　than　that　of　R410A　and　R32,　which　is　comparable　to　R134a.　In　winter　condition,　the　system　energy　efficiency　ratio　(EER)　varies　from　3.　78　to　2.　79　as　the　ambient　temperature　changes　from　12　℃　to　-　12　℃;　in　summer　condition,　the　system　EER　decreases　from　2.　26　to　1.　91　as　the　indoor　temperature　increases　from　29　℃　to　43　℃,　with　a　relatively　constant　cooling　power　at　about　1.　5　kW.　The　discharge　temperature　of　inverter　AC　using　R290　is　far　lower　than　that　of　R32.　However,　there　is　still　great　potential　for　improvement　of　supply　air　temperature　control.　This　study　provides　reference　for　optimization　of　inverter　AC　using　R290.　©　2023　Beijing　University　of　Technology.　All　rights　reserved.