Eu3+ doped ZnO thin films fabricated on Si(111) by pulsed laser deposition were annealed in oxygen and vacuum. XRD spectra show that both the films are (002) oriented, which indicates that both the films are highly c-axis oriented. The structure parameters of the thin films show that the film annealed in oxygen ambient has bigger inter-planar space and smaller stress. When excited under the wavelength of 330 nm, the PL spectra exhibit two bands including a UV band and a DL band, and the ratio of IUV/IDL annealed in oxygen is larger. When excited under the wavelength of 395 nm, only obvious emission at the wavelength of about 595 nm was observed. The characteristic emission of 613 nm belonging to Eu3+ was not observed, which showed that the doped Eu3+ ion occupy inversion center.