The rules of soda lime glass that the refractive index and extinction coefficient varies with the frequency at different temperatures are studied. The dispersion curves of soda lime glass within temperature range of 90~520 K and frequency range of 0.1~1.5 THz by time-domain spectroscopy (TDS) system are measured. We can get the refractive indices and extinction coefficient corresponding to different frequencies by Cauchy equation, which are consistent with the experimental results. Then it can better fit the dispersion curve in a wide range by using temperature correction factor. So a method of solving the refractive indices and extinction coefficients of soda lime glass at different temperatures and different frequencies is got.