Abstract The electronic structures, dielectric functions and absorption coefficient of perfect YAlO 3 (YAP) crystal and YAP crystal containing F 2 center (YAP:F 2 ) have been studied using the CASTEP code with the lattice structure optimized. The calculated electronic structures indicate that the F 2 center in YAP bring donor energy levels in the forbidden band compared with that of perfect YAP. The optical properties of perfect YAP and YAP:F 2 show anisotropy and their optical symmetry coincides with the lattice structure geometry. The calculated polarized absorption spectra of YAP:F 2 exhibit new absorption bands in the region from 190 to 310 nm, which are in agreement with the experimental results.