[en] Ga"3"+-doped Eu_2(MoO_4)_3 films were prepared by electron beam evaporation and annealed at 400 °C–800 °C in oxidizing atmosphere, and the relationship between Ga"3"+ concentration and luminescence properties of the films was explored combining the characterization methods of XRD, excitation, emission spectra and decay curves. It was found that intensity ratio I("5D_0–"7F_2)/I("5D_0–"7F_1) was extremely susceptible to Ga"3"+ concentration, and the luminescence intensity was significantly influenced by the doping of Ga"3"+. The intensity increased with Ga"3"+ concentration ranging from 0 to 0.65 mol and reached a maximum at 0.3 mol and decreased when exceeding 0.65 mol. Finally, the effect of annealing temperature on photoluminescence was also obtained.