C5F10O　as　an　environment-friendly　SF6　substitute　gas　attracts　a　lot　of　attention　due　to　its　excellent　insulation　performance　and　low　global　warming　potential　(GWP).　However,　further　researches　on　insulation　and　arc　extinguishing　performance　of　C5F10O　are　needed　before　large-scale　practical　application.　In　this　paper,　insulation　characteristic　test　platform　was　established　to　test　arc　extinguishing　performance　through　arc　interruption,　and　insulation　performance　through　lighting　impulse　(LI),　and　creeping　discharge.　It　was　found　that　the　positive　and　negative　lightning　impulse　voltages　of　C5F10O/CO2　gas　mixture　with　a　partial　pressure　of　40　kPa　at　0.7　MPa　were　276.3　kV　and　161.46　kV,　which　were　respectively　91.20%　and　88.10%　of　that　of　0.4　MPa　SF6.　The　average　successful　and　unsuccessful　breaking　current　of　the　C5F10O/CO2　gas　mixture　with　a　partial　pressure　of　20　kPa　at　0.7　MPa　were　1　730.2　A　and　1　967.2　A,　which　were　89.7%　and　91.7%　of　that　of　0.4　MPa　SF6.　The　results　show　that　C5F10O/CO2　gas　mixture　is　a　promising　alternative　to　SF6　in　terms　of　insulation　and　arc　extinguishing　performance.　©　2021　IEEE.