Ag2MoO4 ceramic was prepared by using the solid-state reaction method, which could be sintered at 450 degrees C for 2h, having a relative permittivity of 8.08, a Qf value of 17000GHz, and a temperature coefficient of resonance frequency about -133ppm/degrees C. Ag2MoO4 ceramic was chemically compatible with silver but reacted seriously with aluminum to form (Ag0.5Al0.5)MoO4 during the sintering. The fitting of infrared spectra and the Shannon's additive rule were employed to study intrinsic dielectric behaviors of the ceramics at microwave region. Ionic displacive polarization and the electronic polarization contributed almost equally to the dielectric permittivity of the ceramic at microwave region. The Ag2MoO4 ceramics could be a good candidate for ultra-low temperature co-fired microwave devices.