By using high-energy ball-milling method, MgNb₂O₆ powders were synthesized at 800℃ for 2h. Meanwhile, phase transition, sintering behavior, microstructures, and microwave dielectric properties of MgNb₂O₆ ceramics changing with sintering tempreature were investigated. It is found that the calcining temperature of MgNb₂O₆ powders and the sintering temperature of MgNb₂O₆ ceramic are able to be effectively reduced. The pottery of MgNb₂O₆ sintered at 1,220℃ for 2h possesses the average grain size of 3.5μm, ρ= 4.80g/cm³, and excellent microwave dielectric properties of r=19.7 and quality factor Q·f=29,444GHz. Therefore, MgNb₂O₆ pottery obtained by the high energy ball-milling method makes itself become an appropriate candidate for the new generation of middle-temperature sintered high frequency microwave dielectric material.