Bismuth layer-structured ferroelectric ceramics of Na_0.5Bi_4.5-x(Nd_0.5Ce_0.5)_xTi₄O₁₅ (NBT-x, 0.0 ≤ x ≤ 0.4) were synthesized by a traditional solid-state reaction. The effect of (Nd,Ce) substitution for A-site on the microstructure and electrical properties of Na_0.5Bi_4.5Ti₄O₁₅ (NBT)-based piezoelectric ceramics was investigated. X-ray diffraction (XRD) analysis revealed that the (Nd,Ce)-modified NBT ceramics have a pure four-layer Aurivillius type structure. The piezoelectric properties of NBT ceramics were significantly improved by the modification of neodymium and cerium. The Curie temperature T_C gradually decreased from 638 ℃ to 618 ℃ with increasing the (Nd,Ce) modification. The piezoelectric constant d₃₃, mechanical quality factor Q_m, dielectric loss tanδ and Curie temperature T_C of the Na_0.5Bi_4.3(Nd_0.5Ce_0.5)_0.2Ti₄O₁₅ ceramic were found to be 28 pC/N, 3239, 0.0032 and 630 ℃, respectively. Thermal annealing studies indicated that the (Nd,Ce)-modified NBT ceramics possess stable piezoelectric properties, demonstrating that the Na_0.5Bi_4.3(Nd_0.5Ce_0.5)_0.2Ti₄O₁₅ ceramic is a promising candidate for high temperature applications.