The green emitting phosphors, Na2GdPO4F2∶Tb3+, was synthesized by high temperature solid-state method. X-ray diffraction (XRD) and cathodoluminescence (CL) spectrum were used to characterize the samples. Under the low-voltage electron beam (0.5~5 kV) excitation, the Tb3+-doped Na2GdPO4F2 phosphor showed a very strong green emission corresponding to the characteristic transitions of Tb3+ (5D3,4→7FJ transitions, J=6~2) with the strongest emission at 546 nm, corresponding to 5D4→7F5 of Tb3+. The cathodoluminescent color of Na2Gd0.95Tb0.05PO4F2 was green to the naked eye with the Commission International de l’Eclairage (CIE) coordinates of x=0.240 3, y=0.438 6, and the color temperature at about 8 634.3 K. The CL intensity increases upon raising the accelerating voltage, filament current and the doping concentrations, thereinto, the optimal concentrations of Tb3+ is 10 mol%.