(Li_0.5Ce_0.25La_0.25)_xCa_1-xBi₂Nb₂O₉ Aurivillius phase ceramics were prepared via conventional solid-state sintering route. The effects of co-substitution with different types of rare-earth elements on crystal structure, microstructure and electric properties were investigated. Rietveld-refinement analysis showed that the multiple rare earth elements embedded into the lattice point and formed corresponding solid solutions. The crystal structure tended to transform to tetragonal system from pristine orthorhombic system, whereas Bi ³⁺ in A-site with 6s2 lone pair electrons suppressed this change. SEM images exhibited that the grain growth in the direction perpendicular to the c-axis was restrained, which could be attributed to the rare earth oxides’ high melting point and low diffusion during the sintering process. Morphotropic phase boundary of a glide plane between orthorhombic system and pseudo-tetragonal system vanished, which generated spontaneous polarization along a and b axis and resulted in increase of piezoelectric properties. The obtained (Li_0.5Ce_0.25La_0.25)_0.17Ca_0.83Bi₂Nb₂O₉ ceramics performed optimal piezoelectric properties (d₃₃=16.4 pC/N, T_c=913 ℃) and exhibited excellent thermal stability, remaining 85.4% of their initial d₃₃ values after annealing at 850 ℃ for 2 h. All above results demonsrated that the multidoped materials are promising candidates for ultrahigh temperature applications.