The bulk density, sintering behavior and microwave dielectric properties of MgO-2B2O3 series ceramics synthesized by solid-state reaction method were systematically studied in this paper. X-ray diffraction and microstructural analysis revealed that the as-prepared MgO-2B2O3 ceramics possessed a single-phase structure with rod-like morphology. Through the investigation of the effects of different dosages of H3BO3 and BCB on bulk density, sintering behavior and microwave dielectric properties of MgO-2B2O3 ceramics, the optimum sintering temperature was obtained at an addition of 30wt%H3BO3 and 8wt%BCB and the sintering temperature was reduced to 825 oC. The addition of 40wt %H3BO3 and 4 wt%BCB increased the quality factor Q×f, permittivity εr and temperature coefficient of resonance frequency τf of MgO-2B2O3 to 44,306 GHz, 5.1 and -32 ppm/oC, respectively, meeting the criteria of low-temperature co-fired ceramics.