[en] In this study, the shuttle-like CeO₂ particles were synthesized by hydrothermal method and characterized by X-ray diffraction (XRD), TG, scanning electron microscopy (SEM), Photoluminescence (PL), UV–vis and Raman analyses. The cubic fluorite structure and average particle size of ceria were confirmed by XRD. Initially differential thermal analysis and thermal gravimetric were used to analyze the reaction process and chemical mechanism, which suggested a crystallization temperature of the as-synthesized CeO₂ powder at 600 °C. The reaction time and the reaction concentration of the solution were systematically investigated. It is found that the reaction time and the reaction concentration are key parameters for controlling the final morphology. Mixed oxidation states (Ce⁴⁺ and Ce³⁺) were detected in the samples, confirmed using X-ray photo-electron spectroscopy (XPS) and Raman. It has been proven that oxygen vacancies and Ce³⁺ ions exist at the grain surface and at the grain boundaries. The appearance of emission peaks and the visible luminescence peaks can be attributed to the oxygen related defects. The existence of Ce³⁺ ions and oxygen defects existing in shuttle-like CeO₂ samples can lead to the formation of some localized band gap states, which is possibly responsible for the red shifting of band gap. - Highlights: • Shuttle-like CeO₂ particles have been synthesized by a facile hydrothermal method. • Mixed oxidation states (Ce⁴⁺ and Ce³⁺) were detected confirmed by XPS. • The concentrations of Ce⁴⁺ and Ce³⁺ have been listed in detail. • Optical properties were affected by defects on the surface and at the boundaries.