A series of ceria–zirconia–neodymia mixed oxides with different contents of neodymia and the supported Pd-only three-way catalysts before and after aging have been prepared and characterized. The influence of Nd doping on the structural/textural properties of ceria–zirconia (CZ) and the effect on the threeway catalytic performance are also investigated. The results demonstrate that the addition of neodymia results in the formation of ceria–zirconia–neodymia ternary solid solution (CZN) with better textural and structural properties as well as improved reducibility and redox behavior, leading to the promoted threeway catalytic activity and enlarged air/fuel operation window. The modified solid solution with 5 wt.% neodymia shows the preferable textural/structural properties considering that the capacity of foreign cation is limited in the crystal lattice of ceria–zirconia solid solution, and Pd/CZN5 shows the optimum three-way catalytic performance and wider air/fuel operation window, especially for the corresponding aged one.