Ti-doped sapphire crystals were irradiated by the argon fluoride (ArF) excimer laser. Comparing the spectra before and after irradiation, the increasing of absorption spectrum peak at 218 nm is much larger than that at 193 nm and 266 nm. Fluorescence spectra of different figure of merit (FOM) samples at 420 nm were measured, and the results indicated that fluorescence intensity decreased with increasing the FOM. The fluorescence intensity of samples at 420 nm decreased after the excimer laser irradiation. In the EPR spectrum of the Ti-doped sapphire, the intensity of the Ti3+ signal increased after the irradiation. All results indicated that Ti4+ ions changed to Ti3+ ions during the irradiation of the excimer laser.