x (Nd1/2Ta1/2) x O3 lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method. The phase structure, microstructure, and dielectric, ferroelectric and piezoelectric properties of the ceramics were investigated. A reduction of small amount of oxygen vacancies, a significant effect in grain size due to the (Nd1/2Ta1/2)4+ doping, led to the enhancements of the dielectric, ferroelectric and piezoelectric properties of Bi1/2Na1/2Ti1?em class="EmphasisTypeItalic">x (Nd1/2Ta1/2) x O3 ceramics, and the optimized modification was x?=?0.006. The electrical properties of modified samples were deteriorated with further doping (x >0.006), owing to an increase in the concentration of oxygen vacancies. The BNT-NT ceramics with x?=?0.006 was found to have a high remnant polarization (P r ) of 34.7?μC/cm2 and a piezoelectric constant (d 33 ) of 110 pC/N." />