Renormalized Transmission Ellipsometry CRTF,) was applied to a precise measurement of anisotropic refractive indices of nematic liquid crystals. It is quite important for the evaluation to use an monodomain cell with high quality. To realize the good alignment, the alignment film was coated. In this study, the influence of the alignment film thickness and its refractive indices on the accuracy of the measurement is reported. From the numerical analysis and several experiments, it is shown that if n(lambda) > n(0)(lambda) approximate to n(glass) (lambda) is satisfied and n(glass)(lambda) is nearly equal to n(al)(lambda), the evaluated results of n(0)(lambda) and n(e)(lambda) are not influenced by the film thickness d(al). From the results, RTE can be the powerfull tool to measure n(0)(lambda) and of n(e)(lambda) for the LC substances with easy operation.