New high-quality microwave dielectric ceramics Mg2NdNbO6 were prepared by conventional solid-state sintering method. The phases, micro-structures and microwave dielectric properties of Mg2NdNbO6 ceramics were investigated at sintering temperature in the range of 1275 degrees C-1400 degrees C. The X-ray diffraction patterns showed that the peaks of the compounds were attributed to two phases, including the main crystalline phase of NdNbO4 that was indexed as the monoclinic phase and MgO as the second phase. Well-developed microstructures of Mg2NdNbO6 ceramics can be achieved, and the grain size reached the maximum value (1.63 m) at 1375 degrees C. As the sintering temperature increased, the dielectric constant, temperature coefficient of resonant frequency and apparent density remained almost unchanged, however, the significant change in the quality factor was observed. At 1375 degrees C, Mg2NdNbO6 ceramics possessed excellent microwave dielectric properties: epsilon(r) = 16.22, Q x f = 116 000 GHz and (f) = -30.96 ppm/degrees C.