Titanium oxide thin films are prepared at a substrate temperature of 250 A degrees C by electron-beam evaporation and ionassisted deposition. The effects of thermal annealing temperatures from 100 to 450 A degrees C on the optical and mechanical properties are studied. The optical and mechanical properties include refractive indices, extinction coefficients, residual stress, surface roughness and crystallization. Experimental results show these properties of titanium oxide films clearly depend on the thermal annealing process.