Abstract: As mullite ceramic becomes a candidate material for high-capability IC,its foreground becomes wide in the area of electric package substrate,while over-high sintering temperature limits its development.Boracic silicate glass which can be sintered at low temperature was prepared by sol-gel process.Mullite ceramic can be sintered at low temperature when the boracic silicate glass is introduced into it.Proportion of CaO,B₂O₃,SiO₂ was studied and ZnO,P₂O₅ was introduced,and then boracic silicate glass sintered at 800℃ with excellent dielectric properties of linearity shrink rate=22.4%~24.0%,surface ρ=2.21±0.1g/cm³,ε=4.1±0.2,tgδ<0.06%,R_j>1.0×10¹²Ω·cm was obtained.