β-Ga2O3 is a wide band gap semiconductor with a band gap of Eg≈5.0 eV, which has potential optical and optoelectronic applications. The intrinsic β-Ga2O3 and Zn-doped β-Ga2O3 films were prepared on Si (111) and UV transparent quartz substrates using RF magnetron sputtering. The optical transmission, optical absorption, structural property, photoluminescence were measured using a double beam spectrophotometer, X-ray diffractometer, fluorescence spectrometer. The effects of the Zn doping and thermal annealing on the structural and optical properties were investigated. The post-annealed β-Ga2O3 films are polycrystalline. In comparison with the intrinsic β-Ga2O3 films, the intensity of the Zn-doped β-Ga2O3(111) peak becomes weak, the crystallization deteriorates, the (111) peak position shifts from 35.69° to 35.66°. For the post-annealed Zn-doped β-Ga2O3 films, the optical band gap shrinks, the transmittance decreases, the absorption increases, the near-edge absorption appears, and the UV, blue, green emission bands are enhanced. It means that the doped Zn atoms are activated effectively after annealing and act as acceptors.