Ionized　gas　sensors　using　nano　materials　show　good　sensitivity　to　gases.　Therefore,　the　nano　material　structure　has　a　great　impact　on　the　performance　of　sensors.　However,　the　current　researches　have　mainly　focused　on　the　influence　of　nanostructure　on　field　enhancement　factors　without　considering　the　gas　discharge　process　in　space.　Therefore,　these　methods　are　not　suitable　for　the　research　of　ionized　gas　sensors.　In　this　paper,　a　fluid　model　is　established　based　on　the　principle　of　gas　discharge.　It　consists　with　mass　conservation　equation,　energy　conservation　equation,　and　Poisson　equation.　The　influence　of　electrode　separation,　screening　effects　and　nanostructure　on　the　cathode　current　density　was　analyzed　compared　with　the　field　enhancement　factor.　We　not　only　discussed　the　influence　of　nanomaterial　morphology,　but　also　considered　the　influence　of　nanomaterial　quantity　on　gas　discharge,　which　made　the　research　results　somewhat　different　from　the　previous　ones.　The　experimental　results　show　that　the　simulation　results　obtained　by　the　established　model　can　correctly　reflect　the　discharge　characteristics　of　the　ionized　gas　sensor.　The　methods　and　results　presented　in　this　paper　are　expected　to　be　applied　to　the　design　of　device　based　on　gas　discharge.