The effects of $B_2O_3-SiO_2-R(R;CaO,;BaO,;ZnO,;Bi_2O_3)$ borosilicate glass system on the sintering behavior and microwave dielectric properties of ceramic/glass composites were investigated as functions of modifier, glass addition ($30{sim}50;vol%$) and sintering temperature ($500{sim}900^{circ}C$ for 2 hrs). The addition of 50 and 45 vol% glass ensured successful sintering below $900^{circ}C$. Sintering characteristics of the composites were well described in terms of modifier. Borosilicate glass enhanced the reaction with $Al_{2}O_{3}$ to form pores, second phases and liquid phases, which was responsible to component of modifier. Dielectric constant (${varepsilon}_{r},;Q{ imes}f_{o}$) and temperature coefficient of resonant frequency (${ au}_{f}$) of the composite with 50 and 45 vol% glass contents($B_{2}O_{3}:SiO_{2}:R=25:10:65$) demonstrated A-CaBS(7.8, 2,560 GHz, -81ppm/$^{circ}C$), A-BaBs(5.8, 3.130 GHz, -64 ppm/$^{circ}C$), A-ZnBS(5.7, 17,800 GHz, -21 ppm/$^{circ}C$), A-BiBs(45 vol% glass in total)(8.3, 2,700 GHz, -45 ppm/$^{circ}C$) which is applicable to substrate requiring an low dielectric properties.