Abstract: Effects of various amounts of Bi₂O₃ and the heat treatment on sintering and dielectric properties of cordierite-based glass-ceramics were studied. The results show that the addition of Bi₂O₃ and rising sintering temperature promote the densifieation of the sintered bodies. Dielectric constant and dissipation factor of the sintered cordierite-based glass-ceramics are determined by its crystalline structure and the completeness of densification. The dissipation factor decreases with the lifting of sintering temperature, and its curve is similar to the porosity curve. Up to 950%, the dielectric constant of samples increases with the rise of sintering temperature, and its curve is similar to the density curve, too. This material has low dielectric constant（≈5）, low dissipation factor （＜0.2%） and low sintering temperature （as low as 900℃）, so that it can be co-fired with high conductivity metals such as Cu, Au and Ag/Pd paste. It will be a promising material for low-temperature co-fired ceramic substrate.