The　field　emission　electron　source　has　a　wide　range　of　application　value　in　the　field　of　vacuum　electronics,　and　the　realization　of　the　uniformity　and　patterning　of　the　in-situ　growth　of　the　emitter　material　is　the　key　technology.　The　traditional　patterning　process　is　complicated　and　the　pattern　has　not　been　carefully　designed,　resulting　in　uneven　electric　field　distribution.　This　paper　uses　ANSYS　Maxwell　16.0　simulation　software　to　study　the　law　of　electron　motion　trajectory,　and　proposes　a　new　idea　of　the　effective　emission　size　of　the　graphical　emitter　array　and　the　cathode　structure　of　the　optimal　array　spacing　to　improve　the　field　emission　performance.　The　simulation　results　show　that　when　the　array　spacing　d　is　200　μm,　the　electric　field　distribution　in　the　central　area　of　the　patterned　array　is　flat,　and　the　surrounding　area　of　the　array　rises　abruptly.　This　is　mainly　due　to　the　fact　that　the　edge　part　of　the　array　exhibits　the　characteristics　of　a　needle　tip　more　than　the　central　part　of　the　array.　When　d　is　smaller,　the　field　strength　of　the　edge　area　between　the　unit　arrays　is　superimposed,　and　a　field　strength　superimposition　area　appears.　When　d　slowly　increases,　the　edge　superposition　effect　of　the　field　strength　is　weakened,　and　the　electric　field　shielding　effect　is　also　weakened.　Therefore,　when　d　is　larger　(400　μm),　the　field　strength　of　the　cathode　surface　tends　to　be　flat,　because　the　edge　superposition　effect　of　the　field　strength　and　the　electric　field　shielding　effect　are　balanced.　However,　as　d　increases　to　a　certain　extent,　when　the　array　spacing　is　600　μm,　the　center　position　of　the　cell　array　plane　can　be　relatively　far　away,　the　field　emission　of　the　cell　array　is　relatively　independent,　and　the　electron　emission　has　a　neutral　area.　It　can　be　seen　that　when　d　is　selected　at　a　moderate　value,　the　superposition　effect　of　the　field　strength　at　the　edge　of　the　array　is　weakened,　and　there　will　be　no　blind　areas　in　the　surrounding　electric　field,　and　the　electric　field　basically　achieves　a　uniform　distribution.　Subsequently,　according　to　the　simulation　results,　the　patterned　seed　layer　is　accurately　positioned　by　inkjet　printing,　and　then　the　ZnO　nanorod　array　is　hydrothermally　grown.　Field　emission　test　results　show　that　as　d　increases,　the　turn-on　field　strength　Eon　decreases　from　2.95　V/μm　at　200　μm　to　0.57　V/μm　at　400　μm,　and　further　changes　to　2.26　V/μm　at　600　μm.　The　enhancement　factor　b　increases　first　and　then　decreases　as　d　increases　from　200　μm　to　600　μm.　This　is　consistent　with　the　simulation　results,　that　is,　when　the　effective　emission　size　of　the　ZnO　cathode　array　is　200　μm,　when　d　is　400　μm,　the　field　emission　performance　is　optimal,　and　its　turn-on　field　is　0.57　V/μm,　and　the　field　emission　enhancement　factor　is　32　179.　Combining　the　high　efficiency　of　graphic　design　and　inkjet　printing,　it　is　expected　to　realize　a　high-performance　field　emission　electron　source.　©　2022,　Science　Press.　All　right　reserved.