Four types of CeO₂-based oxide samples were prepared by co-precipitation, and their physicochemical properties were characterized by X-ray diffraction (XRD), Raman spectroscopy, N₂ adsorption-desorption (Brunauer-Emmet-Teller method; BET), H₂-temperature-programmed reduction (H₂-TPR), oxygen pulsing technique, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XRD profiles revealed that only broad diffraction lines characteristic of CeO₂ were observed in the case of CeO₂ and CeO₂-Al₂O₃ (CA), while CeO₂-ZrO₂ (CZ) and CeO₂-ZrO₂-Al₂O₃ (CZA) disclosed Ce_0.75Zr_0.25O₂ phase. The paper revealed that homogeneous solid solutions were formed for all the CeO₂-based oxygen storage materials. XPS studies showed that 4+ and 3+ oxidation states of cerium were coexisted on the surface of CZ, CA and CZA_。 However, almost no 3+ oxidation state was detected for pure CeO₂. The best textural properties, higher oxygen storage capacity (OSC) and excellent thermal stability were obtained for CZA. In addition to compare the differences among the four samples, this article proposed a new insight that Al₃₊ might insert among the inter-space of the fluorite structure or highly dispersed in the solid solution. CZA solid solution might be composed of interstitial solid solution and substitutional solid solution, which was verified by the presence of two oxygen species or two types of oxygen channels for CA and CZA. However, the evidence was not detailed enough to sustain this argument, so that further investigation was necessary.