ZnO thin films were grown on Si(111) substrates by pulsed laser deposition (PLD) at various laser repetition frequencies in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural and morphological properties of the films were investigated by X-ray diffraction (XRD) and atom force microscope (AFM) measurements, respectively. The results suggest that films grown at 5 Hz have excellent ultravoilet (UV) emission and high-quality crystallinity. In addition, it is not as expected that the thickness of the films was in direct proportion to laser repetition frequency. The authors think that one laser pulse is not corresponding to one growth instantaneousness. There is a growth ambience containing essential components and partial pressure in the work cavity.