Zinc oxide (ZnO) thin films have been grown on n type Si (100) substrate using femtosecond pulsed laser deposition (PLD). The effect of change in parameters, including substrate temperature, laser energy and oxygen pressure, on the structure and optical properties of ZnO films is discussed. The Xray diffraction results show that the ZnO films are highly caxis oriented when deposited at substrate temperature of 80?℃ with laser energy of 1\^5?mJ under oxygen pressure of 10 mPa. The field emission scanning electron microscopy indicates that the mean grain size increases with the increase of temperature, but decreases with the increase of laser energy. The ultravioletvisible transmissivity shows that the annealed films have a transmittance of 90% in visible rang. The photoluminescence spectra of ZnO films are discussed. In comparison, the structure and photoluminesceme properties of ZnO films produced by using nanosecond PLD are also studied.