Abstract: Effect of substrate temperatures (from 120℃ to 300℃) and heat treatment temperature(400℃) on the structure and optical property of TiO2 thin film deposited by electron beam evaporation method is discussed. The XRD analysis results indicates that the structure of TiO2 thin films deposited on common glass at the substrate temperatures of 120℃, 200℃ and 300℃ is amorphous, and after the heat treatment at 400℃ for one hour,the amorphous structure crystallized and the crystal phase is anatase with strong preferred orientation(004) and the size of the crystalline is within 3.6～8.1nm.The analysis on transmittance spectrum of all samples shows that with the substrate temperature increasing, the refractive index of thin films increases, and after heat treatment higher refractive index of the films is raised due to its crystallizing.