ZnAl2O4 ceramics doped with Li2OB2O3-SiO2 were prepared by conventional solid reaction method. The effect of Li2O-B2O3-SiO2 (LBS) glass on the microwave dielectric properties of ZnAl2O4 was investigated. The phase structure and the microstructure of the ceramics were studied by X-ray diffraction and scanning electron microscopic techniques. The microwave dielectric properties of the sintered samples were measured by the shielded cavity resonance method. The results showed that the sintering temperature of ZnAl2O4 ceramics with 6wt% LBS addition can be effectively reduced from 1 650 ℃ to 1 250 ℃ without second phase formation. The 6wt% LBS doped ZnAl2O4 ceramics sintered at 1 250 ℃ for 3 h have the optimum microwave dielectric properties: εr=7.6,Q×f=24 000 GHz and τf=-58×10-6/℃.