The oxidation behavior of Ti-64 and SP-700 alloys was studied over the temperature range of 700~900℃ in various oxygen-containing atmospheres (at Po2=0.01~1atm). The oxidation kinetics of the two alloys followed the parabolic rate law in all cases. The oxidation rates of the alloys gradually increased with temperature but were independent of oxygen partial pressure, indicating that the scaling of the two alloys possessed an n-type semiconductivity. The scales formed on the alloys consisted mostly of TiO2 and minor amounts of Al2O3, regardless of the oxygen pressure.