(1-x)[0.8Bi(0.5)Na(0.5)TiO(3)-0.2Bi(0.5)K(0.5)TiO(3)]-xBi(Mn0.5Ti0.5)O-3　(x　=　0-0.06,　BNICMT100x)　lead-free　ferroelectric　ceramics　were　prepared　via　solid　state　reaction　method.　Bi(Mna5Tio.5)03　induces　a　structure　transition　from　rhombohedral-tetragonal　morphotropic　phases　to　pseudo-cubic　phase.　Moreover,　the　wide　range　of　compositions　within　x　=　0.03-0.055　exhibit　large　strain　of　0.31%-0.41%　and　electrostrictive　coefficient　of　0.027-0.041　m(4)/C-2.　Especially,　at　x　=　0.04,　the　large　strain　and　electrostrictive　coefficient　are　nearly　temperature-independent　in　the　range　of　25-100　degrees　C.　The　impedance　analysis　shows　the　large　strain　and　electrostrictive　coefficient　originate　from　polar　nanoregions　response　due　to　the　addition　of　Bi(Mn0.5Ti0.5)O-3.