Thermodynamic properties of cubic CeO₂ with pressures up 30 GPa and temperatures up to 2 000 K are studied with first principles combined with a quasi-harmonic Debye model,including temperature dependence of equilibrium volumes,bulk modulus,heat capacity and entropy under ambient pressures.Heat capacity,entropy,Debye temperature and volume thermal expansion coefficient under different pressures are successfully obtained.Calculated heat capacity and entropy are in good agreement with experiments under ambient pressure.