In this paper, Gd2(WO4)3:Eu nanophosphors with different Eu3+ concentrations were synthesized through co-precipitation. The crystal structure and morphology of the nanophosphors were characterized by means of XRD and field emission scanning electron microscopy. Emission and excitation spectra (phonon sideband spectra) of each sample were measured, and concentration quenching curves were also drawn. The optimal doping concentration was confirmed to be 20 mol%. Huang-Rhys factor for each sample of different doping concentration was calculated by the phonon sideband spectra. Fluorescence lifetimes of the samples with different Eu3+ doping concentrations were measured. By fitting the fluorescence lifetime data of Eu3+ 5D0 level within the Auzel's model, the intrinsic lifetime for 5D0 level was determined and the generated phonon number in the quenching process was measured. The energy transfer rate of Eu3+ was derived from the fluorescence lifetime data, and the relationship between the energy transfer rate and the concentration was also given.