The results of studying the evaporation and thermodynamic properties of the TiO2-Al2O3 system in the temperature range 2250-2710 K by high-temperature mass spectrometry are presented. The composition of the vapor is identified, the partial pressures of the TiO2, TiO, and Al vapor species over the studied samples in the indicated temperature range are determined. The determined activities of the components and the excess Gibbs energy in the melt of the TiO2-Al2O3 system at 2345 K point to insignificant deviations from ideality.