Er/Yb co-doped ZnO films were fabricated by using radio-frequency reaction magnetron sputtering technique, and the influences of annealing temperature on the microstructures and photoluminescence (PL) properties of Er/Yb co-doped ZnO films were studied. The results of X-ray diffraction analysis showed that Er/Yb doping induced the crystallite refinement and the vanishment of preferential orientation of the ZnO films and the ZnO crystallite grain size grew with the increase of the annealing temperature. At 900 ℃, Er2O3 and Yb2O3 phases started to precipitate from the film. When the annealing temperature reached to 1000 ℃, a new phase of Zn2SiO4 due to the interfacial reaction of ZnO film with Si chip was observed. At 1200 ℃, ZnO film transited into Zn2SiO4 phase entirely. The PL measurement result indicatcd distinet PL spectra of the films about 1540 nm annealed above 900 ℃ were detected at room temperature and the maximum PL intensity was observed at 1050 ℃. The PL spectra showed typical sharp multi-peak structure characteristic owned by Er3+ ion PL spectra in crystal substrates. The effect on PL properties of the microstructure evolvement of the film was also discussed.