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Abstract: (Gd1−x ,Eu x )2O2SO4 nano-phosphors were synthesized by a novel co-precipitation method from commercially available Gd2O3, Eu2O3, H2SO4 and NaOH starting materials. Composition of the precursor is greatly influenced by the molar ratio of NaOH to (Gd1−x ,Eu x )2(SO4)3 (the m value), and the optimal m value was found to be 4. Fourier transform infrared spectrum (FT-IR) and thermal analysis show that the precursor (m =4) can be transformed into pure (Gd1−x ,Eu x )2O2SO4 nano-phosphor by calcining at 900°C for 2h in air. Transmission electron microscope (TEM) observation shows that the Gd2O2SO4 phosphor particles (m =4) are quasi-spherical in shape and well dispersed, with a mean particle size of about 30–50nm. Photoluminescence (PL) spectroscopy reveals that the strongest emission peak is located at 617nm under 271nm light excitation, which corresponds to the 5D0 → 7F2 transition of Eu3+ ions. The quenching concentration of Eu3+ ions is 10mol% and the concentration quenching mechanism is exchange interaction among the Eu3+ ions. Decay study reveals that the 5D0 → 7F2 transition of Eu3+ ions has a single exponential decay behavior. [Copyright &y& Elsevier]