Ta2O5 thin films were prepared by reactive magnetron sputtering technique. The microstructure,morphology and optical properties of the films deposited at different substrate temperature were investigated by X-ray diffraction, scanning electron microscopy( SEM) and spectrophotometer. The Ta2O5 thin film begin to crystallized when substrate temperature reach to 450 ℃. The films were amorphous when temperature was less than 450℃,and the transmittance of thin films would increase with the enhancing substrate te...