SF6　gas　is　widely　used　in　power　equipment　for　its　excellent　arc　extinguishing　and　insulation　properties.　However,　SF6　is　a　strong　greenhouse　effect　gas　with　a　global　warming　potential　(GWP)　of　23,　500　times　that　of　CO2.　The　research　on　SF6　environmental　alternative　gas　has　made　great　progress　these　years.　C4F7N　is　considered　the　most　likely　gas　to　replace　SF6　in　the　near　future.　Although　C4F7N　have　the　good　arc　extinguishing　property,　the　arc　extinguishing　mechanism　of　it　in　35kV　circuit　breaker　is　not　clear.　Because　arc　extinguishing　is　a　complex　physical　and　chemical　process　involving　the　interaction　of　gas　flow　fields,　electromagnetic　fields,　and　ablation　the　nozzle　materials.　It　is　difficult　to　quantitatively　and　directly　evaluate　the　interruption　performance　of　circuit　breakers.　In　this　paper,　a　method　combining　the　simulation　of　the　arcing　process　and　the　evaluation　of　the　post-arc　recovering　ability　for　studying　the　characteristics　of　the　arcing　and　post-arc　recovering　of　the　C4F7N/CO2　mixed　gas　is　applied　to　35kV　circuit　breaker.　The　temperature,　pressure　and　airflow　field　characteristics　during　the　arc　burning　process　are　compared　and　analyzed.　Finally,　through　the　post-arc　recovering　analysis,　the　post-arc　currents　at　different　rising　rate　of　recovery　voltage　(RRRV)　and　zero-front　current　change　rates　(di/dt)　are　calculated,　and　the　interruption　performance　of　C4F7N/CO2　mixed　gas　and　SF6　gas　is　obtained.　By　combining　the　Magnetohydrodynamics　(MHD)　analysis　and　the　Mayr　arc　model　the　interruption　processes　for　a　35kV　circuit　breaker　filled　with　5%　C4F7N/CO2　at　0.8　MPa,　as　well　as　SF6　at　0.7　and　0.8　MPa,　are　investigated.　It　can　provide　a　certain　theoretical　reference　for　the　application　of　C4F7N/CO2　mixed　gas　in　power　equipment.　©　2021　IEEE.