Influences　of　calcination　temperature　(Tcal)　on　discontinuous　grain　growth　(DGG),　and　related　grain　size　effect　on　structure/ferroelectric/electrocaloric　properties　were　studied　and　compared　in　fine-/large-grain　Ba(Ti0.85Zr0.15)O3　ceramics.　DGG　phenomena　from　several　to　＞100　μm　are　all　observed　with　rising　sintering　temperature　(TS).　Increasing　Tcal　(1200–1320　°C)　can　cause　larger　powders　but　decrease　the　sintering　activity,　leading　to　a　higher　critical　TS　(1320–1360　°C)　of　DGG.　Relatively　high　Tcal　(larger　powder　size)　will　lead　to　smaller　ceramic　grains　and　density　before　DGG,　while　being　prone　to　obtain　larger　grains　and　stronger　ferroelectric　correlations,　but　lower　density　after　DGG.　The　over-sized　powders　and　smaller　grains/density　will　present　in　ceramics　if　Tcal　closes　to　critical　TS.　In　fine-　and　large-grain　ceramics,　grain　size　variation　is　similar　to　the　evolution　of　dielectric,　ferroelectric　polarization,　and　electrocaloric　properties,　but　shows　an　opposite　variation　trend　with　coercive　field　and　relaxor　phase　transition.　Electrocaloric　strength　of　fine-grain　ceramics　increases　with　a　rising　electric　field　due　to　their　difficult　domain　switching,　while　an　opposite　trend　shows　in　large-grain　ceramics.　Finally,　higher　electrocaloric　properties　are　obtained　in　ceramics　with　relatively　big　grains　because　of　easier　polarization　rotation,　higher　polarization,　and　polarization　change　rate.　©　2024　Elsevier　Ltd