Li2O-Nb2O5-TiO2(LNT) microwave dielectric ceramics of cubic crystal system were synthesized by the traditional solidstate reaction method.The effects of LAB(LiAlB) doping on sintering character and electric properties of the samples were studied using XRD,SEM and microwave dielectric properties measurements.The results show that adding LAB in the LNT ceramic will effectively promote the sintering,and significantly improve the dielectric constant and the quality factor.When the mass fraction of LAB reaches to 4%,the sample pellets were sintered at temperatures of around 900 ℃ for 2 h,and shows the best microwave performances of dielectric constant εr=18.05,quality factor times frequency Q×f=22 040GHz(f=6.41 GHz),and temperature coefficient of frequency τf=-20.74×10-6/℃.