(1−x) (Bi 0.5 (Na 0.82 K 0.18 ) 0.5 ) TiO 3 –x BiAlO 3 [(1−x) BNKT18–x BA] lead-free piezoelectric ceramics were synthesized by conventional solid-state reaction method. Structure and electrical properties of (1−x) BNKT18–x BA ceramics were investigated. X-ray diffraction (XRD) data shows that (1−x) BNKT18–x BA ceramics form the pure perovskite phases. Scanning electron microscope (SEM) images indicate that the grain sizes of (Bi 0.5 (Na 0.82 K 0.18 ) 0.5 ) TiO 3 (BNKT18) ceramics decrease with the addition of BiAlO 3 (BA). At room temperature, the ferroelectric and piezoelectric properties of the BNKT18 ceramics have been improved by the addition of appropriate BA. At room temperature, the remnant polarization P r , piezoelectric coefficient d 33 , planar coupling factor k p and relative dielectric constant ε r of (1−x) BNKT18–x BA ceramics at x=0.0075 all reach maximum values: P r =39.3μC/cm 2 , d 33 =171pC/N, k p =0.3128 and ε r =1583.