Ceramic composites of B2O3-Bi2O3-SiO2-ZnO (BBSZ) glass mixed with Al2O3 (10-50vol%) were sintered at 450 degrees C, and their microstructural and dielectric properties investigated. Dense structures were obtained when the Al2O3 content was lower than 30vol%. Raman, XRD, and FESEM showed the existence of a secondary phase, Bi24Si2O40, in all samples. The dielectric properties of the composite with 30vol% addition of Al2O3 showed good dielectric properties with epsilon(r) of 14.8 and 20.8 and 32.5 at 100kHz and 100MHz and 1GHz, respectively. The tan values at the same frequencies were 0.004 and 0.006 and 0.016. The results show that BBSZ glass with different amounts of Al2O3 exhibit widely applicable relative permittivity values and affordable loss and are thus promising candidates for ultra-low sintering temperature applications.