In this research, the effects of an Al 2 O 3 nanoparticle additive on the structure and electrical properties of Pb 0.88 Sr 0.12 Zr 0.54 Ti 0.44 Sb 0.02 O 3 (PSZST) ceramics were investigated. The PSZST ceramics with the addition of 0 -2.0 vol % Al 2 O 3 were fabricated via a solid-state mixed oxide method and sintering at 1250°C for 2 h to obtain dense ceramics. X-ray diffraction indicated that all compositions exhibited a single perovskite structure. Phase identification showed coexisting mixed rhombohedral and tetragonal phases for the modified ceramics, while the unmodified ceramics showed a rhombohedral-rich phase. The addition of Al 2 O 3 nanoparticles was also found to improve the densification and the electrical properties of the PSZST ceramics, such as dielectric constant and polarization. The 2.0 vol% sample showed the highest low-field piezoelectric coefficient (d 33 ) value of 646 pC/N, which was 90% higher than that of the unmodified sample, suggesting that this composition had the potential to be one of the promising piezoelectric ceramic candidates for further use in actual applications.