The　electrostrictive　effect　has　some　advantages　over　the　piezoelectric　effect,　including　temperature　stability　and　hysteresis-free　character.　In　the　present　work,　we　report　the　diffuse　phase　transitions　and　electrostrictive　properties　in　lead-free　Fe＜sup＞3+＜/sup＞-doped　0.5Ba(Zr＜sub＞0.2＜/sub＞Ti＜sub＞0.8＜/sub＞)O＜sub＞3＜/sub＞-0.5(Ba＜sub＞0.7＜/sub＞Ca＜sub＞0.3＜/sub＞)TiO＜sub＞3＜/sub＞　(BZT-0.5BCT)　ferroelectric　ceramics.　The　doping　concentration　was　set　from　0.25　to　2　mol　%.　It　is　found　that　by　introducing　Fe＜sup＞3+＜/sup＞　ion　into　BZT-0.5BCT,　the　temperature　corresponding　to　permittivity　maximum　T＜sub＞m＜/sub＞　was　shifted　toward　lower　temperature　monotonically　by　37　°C　per　mol　%　Fe＜sup＞3+＜/sup＞　ion.　Simultaneously,　the　phase　transitions　gradually　changed　from　classical　ferroelectric-to-paraelectric　phase　transitions　into　diffuse　phase　transitions　with　a　weak　relaxor　characteristic.　Purely　electrostrictive　responses　with　giant　electrostrictive　coefficient　Q＜sub＞33＜/sub＞　between　0.04　and　0.05　m＜sup＞4＜/sup＞/C＜sup＞2＜/sup＞　are　observed　from　25　to　100　°C　for　the　compositions　doped　with　1-2　mol　%　Fe＜sup＞3+＜/sup＞　ion.　The　Q＜sub＞33＜/sub＞　of　Fe＜sup＞3+＜/sup＞-doped　BZT-0.5BCT　ceramics　is　almost　twice　the　Q＜sub＞33＜/sub＞　of　other　ferroelectric　ceramics.　These　observations　suggest　that　the　present　system　can　be　considered　as　a　potential　lead-free　material　for　the　applications　in　electrostrictive　area　and　that　BT-based　ferroelectric　ceramics　would　have　giant　electrostrictive　coefficient　over　other　ferroelectric　systems.