(Bi0.5Na0.5)Ti1-xCoxO3　(0≤x≤0.015)　lead-free　piezoceramics　were　prepared　by　the　conventional　solid　phase　method.　All　the　BNT　specimens　presented　a　monoclinic　phase　of　Cc　in　crystal　structure　and　the　addition　of　Co　caused　a　remarkably　promoted　grain　growth.　Simultaneously,　Co　cation　enters　into　the　B-site　of　the　perovskite　lattice,　forming　the　hard　doping　effect,　the　oxygen　vacancies　in　the　lattice　are　generated,　the　internal　bias　field　of　BNT　increased,　and　the　temperature　stabilization　of　BNT　ferroelectricity　is　improved.