Abstract: Based on density functional theory and Boltzmann transport equation, this paper investigates the elastic properties, thermodynamic properties, and lattice thermal conductivity of CeO₂ under high pressure. CeO₂ exhibits lattice dynamic stability within 0 GPa-30 GPa. At 300 K, the lattice thermal conductivity of CeO₂ is 10.02, 14.92, 20.97, and 26.75 W·（m∙K）^–1 at 0, 10, 20, and 30 GPa, respectively. Acoustic phonons contribute more to the lattice thermal conductivity of CeO₂ than optical phonons. The increase in lifetimes under high pressure is the main reason for the significant increase in thermal conductivity of CeO₂. As a comparison, the Ab-initio Molecular Dynamics (AIMD) based on machine learning is used to simulate the phonon and lattice thermal conductivity of CeO₂ at 0 GPa. The lattice thermal conductivity obtained by AIMD at 300 K and 0 GPa is 11.19 W·（m∙K）^–1.