The　extended　Eshelby　method　and　Ginzburg-Landau　theory　have　been　employed　to　investigate　the　effect　of　grain　boundary　on　the　microstructure　behavior　and　electromechanical　property　of　BaTiO3　ceramics　with　no　prior　constraint　on　the　grains＇　shape　and　material　parameters.　The　results　obtained　show　that,　the　ferroelastic　property　of　grain　boundary　plays　an　important　role　on　the　domain　structure,　ferroelectric　and　electromechanical　properties　of　ferroelectric　ceramics　by　affecting　the　elastic　and　electrostatic　field　of　the　material.　The　macro-properties　of　ferroelectric　ceramics　could　be　effectively　functionalized　by　controlling　the　average　grain　size　and　ferroelastic　field　of　the　structure.　(C)　2019　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.