SiO2 films are deposited on Si and sapphire (α-Al2O3) substrates by Dual Ion beam sputtering method. The microstructure, surface morphology，residual stress and optical stability of SiO2 coating in the wavelength of 0.4~1.2 μm and 3~5 μm are investigated, systematically. The results indicate that the residual stress goes through a local minimum value at ~400 ℃. There is a close relationship between the optical constant and the surface conditions, residual stress, microstructure of SiO2 film. As the temperature increases up to 1 000 ℃, SiO2 film can keep well thermal stability without notable damage morphology. The result can give some guidance for designing the optical coatings used in harsh environments.