Inhomogeneous　electrical　performance　in　ZnO　varistor　ceramics　are　investigated　from　distribution　of　intrinsic　point　defects　using　thermally　stimulated　depolarization　current　(TSDC).　The　nonlinear　coefficient　is　50　in　central　area　while　it　is　only　25　at　the　brim.　Meanwhile,　the　leakage　current　density　increases　from　2.9　μA/cm2　in　the　center　to　14.7　μA/cm2　at　the　brim.　From　X-ray　detection,　phase　compositions　in　the　center　and　at　the　brim　show　no　difference.　At　the　same　time,　grain　size　distribution　is　relatively　uniform　among　the　ZnO　sample,　indicating　non-uniform　grain　boundary　characteristics　should　be　responsible　for　the　electrical　inhomogeneity.　From　analysis　of　TSDC,　it　is　found　that　intrinsic　point　defect　distributions　are　inhomogeneous.　The　densities　of　zinc　interstitials　and　oxygen　vacancies　are　much　higher　at　the　brim　than　those　in　the　center.　The　higher　intrinsic　defect　densities　at　the　brim　might　induce　higher　donor　density　in　the　depletion　layers　at　Schottky　barriers　resulting　in　lowered　Schottky　barrier,　which　is　in　accordance　with　the　result　of　Schottky　barrier　height　calculated　from　dc　current.　Therefore,　the　electrical　inhomogeneity　in　ZnO　varistor　ceramics　is　understood　from　the　aspect　of　intrinsic　point　defect　distribution.　©　2018　IEEE.