By combining Swanepoels theory and the Wemple-DiDomenico dispersion model， a simple method was established to determine the optical constants of the sol-gel derived ZrO2 films directly from the corresponding transmission spectra. The results showed that the sol-gel ZrO2 films exhibite the optical characteristics of high refractive index of 1.63—1.93 (at 632.8nm)， negligible absorption in spectral region of 400—1200nm， as well as the direct band gap of about 4.97—5.63eV. And the specific values of the optical constants strongly depend on the annealing temperature, which is one of the important technologicalparameters for the sol-gel preparation of ZrO2 films. Moreover， in the weakand medium absorption spectral regions， the calculated values of refractive indices are in satisfactory agreement with the results derived from the high-resolution Tek 3000 film-characterization system， indicating the reliability and feasibility of the method in determining the optical constants of ZrO2 films.