(1-x)Bi1/2Na1/2TiO3-xPbMg(1/3)Nb(2/3)O(3)[(1-x)BNT-xPMN] ceramics have been fabricated via a conventional solid-state method for compositions x 0.3. The microstructure, phase structure, ferroelectric, and dielectric properties of ceramics were systematically studied as high-temperature capacitor materials. XRD pattern certified perovskite phase with no secondary phase in all compositions. As PMN concentration increased, the phase of (1-x)BNT-xPMN ceramics transformed from ferroelectric to relaxor gradually at room temperature, with prominent enhancement of dielectric temperature stability. For the composition x = 0.2, the temperature coefficient of capacitance (TCC) was <15% in a wide temperature range from 56 to 350 degrees C with high relative permittivity (>3300) and low dielectric loss (<0.02) at 150 degrees C, which indicated promising future for (1-x)BNT-xPMN system as high-temperature stable capacitor materials.