Generally,　the　central　conductor　or　conducting　electrodes　will　be　polished　during　the　manufacture　process　according　to　certain　standards.　Yet　even　if　the　electrodes　are　appropriately　treated,　the　contact　between　the　central　conductor　and　insulation　material　will　not　be　a　perfect　contact.　There　will　be　air　gaps　at　certain　places.　How　will　the　air　gaps　between　metal　electrodes　and　insulation　materials　influence　the　charge　injection　behaviors　at　the　interface,　is　an　interesting　topic.　To　study　this　issue　systematically,　firstly,　the　PEA　system　is　improved　and　modified　in　order　to　measure　the　space　charge　characteristics　in　a　larger　temperature　range.　Secondly,　aluminum　electrodes　with　the　same　size　are　polished　by　sandpapers　with　different　mesh　numbers　to　obtain　different　surface　roughness.　Thirdly,　a　confocal　microscope　is　used　to　observe　the　three-dimensional　morphology　of　electrodes　with　different　surface　roughness.　Then　the　space　charge　injection　behaviors　are　measured　and　analyzed　at　80　C　with　different　electrodes.　The　research　provide　results　that　show　the　relationship　between　surface　roughness　of　electrodes　and　the　charge　injection　characteristics,　which　is　of　great　significance　to　the　manufacture　and　production　of　metal　electrodes　in　the　electrical　engineering　industry.　©　2018　IEEE.