Using high purity SiO2 and alumina powder as starting materials,Al2O3 packaging ceramics were obtained by conventional solid state reaction method at 1 580 ℃ in ambient air.The effects of SiO2 additive on the thermal properties mechanical properties and dielectric properties of Al2O3 ceramics were studied.The results showed that when the SiO2 doped amount was 3.5%,the integrated performance of the sample sintered at 1 580 ℃ was the best.The density of sample was 3.85 g/cm3,the bending strength of samples was 517 MPa,the coefficient of thermal expansion(CTE)was 6.6×10-6(300 ℃）, and the dielectric constant was 9.4.