The behavior of dielectric and microwave properties against sintering temperature was been carried out on CaO-B2O3-SiO2 glass-ceramics with Na2O addition by XRD and SEM. The results show that 0.5 wt.% Na2O addition is advantageous to improve the dielectric and microwave properties due to increasing the major crystalline CaSiO3. With further increasing Na2O content, α-SiO2 is the predominant crystalline phase instead of CaSiO3. The CBS glass-ceramics with 0.5 wt.% Na2O sintered at 875°C has a bulk density of 2.51g·cm-3, and which possesses good dielectric properties: er =6.2, tanδ=1.9×10-3(10 MHz) and low dielectric constant below 2×10-3 over a wide frequency range. The proposed dielectrics can find applications in microwave devices, which require low dielectric loss and low dielectric constant.