For low temperature co-fired ceramics (LTCC) materials, BaO-B2O3-MgO-Al2O3 glass system was tested. The starting temperature for densification of a sintered body was at 700°C and the onset temperature for crystallization of a sintered body was 820°C. With the sintering temperature, the sintered body was investigated with shrinkage, crystal phases, thermal properties, and mechanical properties. The glass transition temperature was constant with increasing frit size. However, the onset point of crystallization increased with increasing frit size. The formation of crystal phase was celsian (BaAl2Si2O8). From our results, it is possible to achieve the glass-ceramic having the high strength and the ability of sintering at low temperature using controlling the sintering temperature of BaO-B2O3-MgO-Al2O3 system glass frit.