The extended Cauchy model is a common model for describing the birefringence dispersion of liquid crystal mixture, however, in ultraviolet spectral ranges, the extended Cauchy model can not fit well with the experimental data. Here, we report a Sellmeier model for fitting the birefringence dispersion of liquid crystal mixture in a broad wavelength range from ultraviolet to near infrared. For this purpose, the principal birefringence values were accurately measured using spectroscopic ellipsometer and the Sellmeier coefficients were then obtained by a nonlinear fitting method. The results show that the χ2 of the Sellmeier model is 0.0019 and the χ2 of the extended Cauchy model is 0.0349. In addition, at the standard test wavelength of 589 nm and the ultraviolet wavelength of 378 nm, the fitting values show that the Sellmeier model were closer to the measured values. Both experimental result and χ2 test demonstrate that Sellmeier model has a better fit than extended Cauchy model.