The dielectric properties and the microstructures of 0.5LaAlO(3)-0.5SrTiO(3) ceramics with B2O3 additions (0.25 - 1 wt%) prepared with conventional solid-state route have been investigated. Doping with B2O3 (up to 0.5 wt%) can effectively promote the densification and the dielectric properties of 0.5LaAlO(3)-0.5SrTiO(3) ceramics. It is found that LaAlO3-SrTiO3 ceramics can be sintered at 1400 degreesC due to the liquid phase effect of B2O3 addition observed by Scanning Electronic Microscopy. The dielectric constant as well as the Q X f value decreases with increasing B2O3 content. At 1430 degreesC, 0.5LaAlO(3)-0.5SrTiO(3) ceramics with 0.25 wt% B2O3 addition possesses a dielectric constant (epsilon (r)) of 34.5, a Q X f value of 43,200 (at 7 GHz) and a temperature coefficient of resonant frequency (tau (f)) of - 10.7 ppm/degreesC.