The optical parameters of GeTe semiconductor films prepared and annealed at different temperatures have been measured by using a new method. A compared study by means of using a spectrum ellipsometer is presented. The optical parameters of the samples are obtained through the processes of data simulation and correction of the old calculation model. In the meantime, the data calculations of the same samples measured by a spectrum ellipsometer are presented, and the complex refractive index curves of them in the spectrum range from 250 nm to 830 nm are obtained.