The formation process and microwave dielectric properties of the Mg2V2O7 ceramics were investigated. The MgV2O6 phase that was formed at around 450 degrees C interacted with remnant MgO above 590 degrees C to form a homogeneous monoclinic Mg2V2O7 phase. Finally, this monoclinic Mg2V2O7 phase was changed to a triclinic Mg2V2O7 phase for the specimen fired at 800 degrees C. Sintering at 950 degrees C for more than 5 h produced high-density triclinic Mg2V2O7 ceramics. In particular, the Mg2V2O7 ceramics sintered at 950 degrees C for 10 h exhibited the good microwave dielectric properties of epsilon(r)=10.5, Q x f=58 275 GHz, and tau(f)=-26.9 ppm/degrees C.