Athree-dimensionalglobalchemistrytransportmodel(OSLOCTM2)isusedtoinvestigatetheimpactofsubsonicaircraftNOxemissiononNOzandozoneoverChinaintermsofayear2000scenarioofsubsonicaircraftNOxemission.TheresultsshowthatsubsonicaircraftNOxemissionsignificantlyaffectsnorthernChina,whichmakesNOxat250hPaincreasebyabout50pptvwiththehighestpercentageof60%inJanuary,andleadingtoanozoneincreaseof8ppbvwith5%relativechangeinApril.TheNOxincreaseismainlyattributedtothetransportprocess,butozoneincreaseisproducedbythechemicalprocess.TheNOxincreasesbylessthan10pptvbyvirtueofsubsonicaircraftNOxemissionoverChina,andozonechangeslessthan0.4ppbv.WhensubsonicaircraftNOxemissionoverChinaisdoubled,itsinfluenceisstillrelativelysmall.