Abstract: Magnesium borate ceramics with different Mg/B mole ratio were prepared by the traditional two steps solid-state reaction method.The addition of sintering aidswasused to lower the sintering temperature of ceramics.The result shown that magnesium borate microwave ceramics possessed low dielectric loss in a wide composition range. Whenthe Mg/B mole ratio was 1.25:1, 10 wt% LBSCA glass added magnesium borate ceramic sintered at 900℃ exhibited the optimum microwave dielectric performance with ε_r= 6.92, Q×f=31.8×10³ GHz（f=12 GHz）, indicating that this material is a candidate for LTCC technology application.