0.1, 1.0, 3.0, and 5.0% Dy-doped Na3AlF6 ceramics were synthesized by the spark plasma sintering method, and optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) properties were investigated. Under the optical stimulation at 730 nm, Dy-doped Na3AlF6 ceramics after X-ray irradiation showed OSL peaks at 480 and 580 nm due to the 4f–4f transitions of Dy3+. The TSL glow peaks were detected at 120, 330, and 400 °C in Dy-doped Na3AlF6 ceramics. The 1% Dy-doped sample indicated the highest luminescence intensity in both OSL and TSL, and the intensity decreased when Dy concentration exceeded 3%. In terms of detector property, the 1 and 3% Dy-doped Na3AlF6 ceramics had linear dose responses over the range of 0.1–1000 mGy in the TSL measurement.