Abstract:BaO-B2O3-SiO2 Glass-ceramics with high thermal expansion coefficient was made by solid state method.The phase composition and microstructure of the Glass ceramics were characterized by SEM and XRD.It turned out that the thermal expansion coefficient and dielectric loss increased with the content of Cr2O3.The results showed that the crystal growth was accelerated because of Cr2O3,and the quartz was transformed into the cristobalite.Because of the high thermal expansion coefficient of cristobalite,the increase of cristobalite accounted for the increase of the thermal expansion coefficient of Glass ceramics.The BaO-B2O3-SiO2 Glass ceramics were made with high thermal expansion coefficient (18.44×10-6/℃),high bending strength(187 MPa) and low dielectric constant(5.5) when the mass fraction of Cr2O3 was 0.5%.