TiO2　ceramics　possess　excellent　microwave　dielectric　properties,　but　defects　have　a　great　influence　on　the　dielectric　properties　of　materials.　Compared　with　the　TiO2　sintered　under　air(Resistivity　=　109　Ωm,　Εr≈　78.62,　3.2 GHz),　in　N2　atmosphere,　the　TiO2　ceramic　has　a　resistivity　of　100　Ωm,　Εr≈　105(1 kHz),　and　the　microwave　performance　degenerates.　It　proves　that　the　oxygen　vacancy　defect　formed　in　the　anoxic　environment　is　the　main　reason　of　the　change　of　electrical　properties.　Based　on　the　above　analysis,　TiO2　(N2)　ceramics　are　annealed　under　air　at　different　temperatures.　As　the　annealing　temperature　increases　to　1200 °C,　the　resistivity　of　TiO2　returns　to　109　Ωm,　Εr≈　100(around　3 GHz),　and　the　forbidden　band　width　gradually　increases　to　2.86 eV　from　1.42 eV,　confirming　the　annealing　treatment　method　can　reduce　the　concentration　of　material　defects,　so　that　the　electrical　properties　of　TiO2　ceramics　are　better　restored.　©　2020,　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.