Tb 3+ -doped Sr 3 Gd(BO 3 ) 3 phosphor was prepared by solid-state reaction and characterized by X-ray diffraction (XRD) and cathodoluminescence (CL) spectrum. XRD reveals that the Tb 3+ ions have been doped into the Sr 3 Gd(BO 3 ) 3 host lattice. The optimum doping concentration of Tb 3+ is 5mol%. Under the excitation of low voltage electron beams (1.0–7.0kV), the Sr 3 Gd 0.95 (BO 3 ) 3 :0.05Tb 3+ phosphor shows the characteristic emissions of Tb 3+ ( 5 D 3,4 → 7 F J , J=3–6 transitions) with the strongest emission around 545nm. The emission intensity of optimal composition Sr 3 Gd 0.95 (BO 3 ) 3 :0.05Tb 3+ is comparable with that of commercial Zn 2 SiO 4 :Mn 2+ phosphor with chromaticity coordinates of (0.2415, 0.4663). The optical properties study suggests that it could be potential candidate as a green-emitting phosphor for field emission displays (FEDs) application.