A series of Gd2(MoO4)3∶Eu3+ phosphors were prepared by a sol-gel combustion method with citric acid as complexing agent. The structure, morphology and luminescence properties of Gd2(MoO4)3∶Eu3+ phosphors were characterized by XRD, SEM and fluorescence spectrum. The results of XRD indicate that Gd2(MoO4)3∶Eu3+ phosphors with monoclinic system could be obtained by annealing precursor of molar ratio of rare earth ions to citric acid being 1∶0.5 at 800 ℃. The phase transformation from Gd2(MoO4)3∶Eu3+ phosphors with monoclinic to orthogonal structure could be achieved by changing annealing temperature and the molar ratio of rare earth ions to citric acid. The morphology of Gd2(MoO4)3∶Eu3+ phosphors are affected by synthesis conditions. The results of fluorescence spectra show that a main emission peak of Gd2(MoO4)3∶Eu3+ phosphors is at 616 nm due to the 5D0→7F2 electric dipole transition of Eu3+. The emission intensity of Gd2(MoO4)3∶Eu3+ phosphors with orthogonal crystal system was significantly stronger than that of monoclinic system. The 5D0→7F2/5D0→7F1 relative emission intensity ratios calculated show the local symmetry environment around Eu3+ increases in Gd2(MoO4)3∶Eu3+ phosphors with orthogonal structure compared with that of monoclinic structure.