ZnO thin films were deposited on n-Si (111) at various substrate temperatures and oxygen pressures by pulsed laser deposition (PLD) using a Nd∶YAG laser with the wavelength of 1064 nm. X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the microstructure, optical property and morphology of the ZnO thin films. A comparatively optimal crystallized ZnO thin film was obtained at the substrate temperature of 600 ℃ in oxygen pressure of 50 mTorr. The intensity of the luminescence strongly depends on the stoichiometry of the film as well as the crystalline quality.