Red phosphors of Gd1-xAl3(BO3)4:Eux3+ were synthesized by using the solid-state reaction method. The phasestructure and morphology of the phosphors were measured using X-ray diffraction (XRD) and field emission-scanning electronmicroscopy (FE-SEM), respectively. The optical properties of GdAl3(BO3)4:Eu3+ phosphors with concentrations of Eu3+ ions of0, 0.05, 0.10, 0.15, and 0.20mol were investigated at room temperature. The crystals were hexagonal with a rhombohedrallattice. The excitation spectra of all the phosphors, irrespective of the Eu3+ concentrations, were composed of a broad bandcentered at 265nm and a narrow band having peak at 274nm. As for the emission spectra, the peak wavelength was 613nmunder a 274nm ultraviolet excitation. The intensity ratio of the red emission transition (5D0→7F2) to orange (5D0→7F1) showsthat the Eu3+ ions occupy sites of no inversion symmetry in the host. In conclusion, the optimum doping concentration of Eu3+ions for preparing GdAl3(BO3)4:Eu3+ phosphors was found to be 0.15mol.