The (Bi0.5(Na0.80K0.20)0.5)1- x (Ba0.7Sr0.3) x TiO3 or (BiNK)1- x (BaS) x T (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 mol fraction) lead-free piezoelectric ceramics were firstly made by a conventional one step mixed-oxide method and sintered at 1125 °C for 2 h with a heating rate of 5 °C/min. All samples showed optimum relative densities of ∼97–98%. The XRD result indicated that no impurity phase was detected in all fabricated samples. SEM images indicated that all ceramics possessed irregular shaped grains. It was also found that BST added content had an effect on electrical properties of BNKT ceramics. The highest piezoelectric coefficient (d33 = 164 pC/N) with good dielectric (εr = 1577, tanδ = 0.0855) and ferroelectric properties (Pr = 11.38 µC/cm2, Ec = 19.89 kV/cm) were obtained for (BiNK)0.98(BaS)0.02T sample.