Diamond-like carbon films were deposited by high-frequency and high-power pulse d XeC1 excimer laser ablation of pyrolytic graphite targets in a high vacuum ch amber at room temperature. The effects of the laser power density on the propert ies and structures of the films were studied by setting the laser power density on the target at 108, 109 and 1010W/cm2. The optical transparency and the optical band gap as well as the electron diffraction patterns and Raman spectra of the films were investigated. The results demonstrated that the stru ctures of the films varied from amorphous to nanocrystalline diamond with the l aser power density increasing from 108 to 1010W/cm2.