The (Bi0.5Na0.5)0.94Ba0.06Ti1-x (Nd0.5Ta0.5) xO3 (0.01≤x≤0.05) lead-free ceramics (BNBT-xNT) used (Nd0.5Ta0.5)4+ complex-ions to modify its structure and electrical properties. The BNBT-xNT ceramics exhibit the coexistence of tetragonal and rhombohedral phase. The (Nd0.5Ta0.5)4+ complex-ions prohibit grain growth, and its average grain size decreases from 2.53 µm to 0.84 µm with increasing complex-ion content. The NT doping not only induces the transformation from ferroelectric phase to relaxor ferroelectric phase but also decreases the coercive field and remnant polarization. The permittivity curves are broadened at heavily doping content. The energy storage and strain properties are improved by complex-ions. The maximum energy storage density of 0.475 J/cm3 is obtained at x = 0.035 and 60 kV/cm, the energy storage efficiency achieves the maximum efficiency of 61.5% at x=0.05. As increasing complex-ion content, the typical butterﬂy-shaped strain curve develops into a sprout-shaped one, and the maximum strain of 0.199% is obtained at x=0.02.