For the need of wave-transparent and the heat resistant materials of the flight vehicle in high march number severe thermal environment, aerogels composites were prepared via sol-gel process and supercritical CO2 drying process and the post-processing that were obtained using wave-transparent quartz fibers as reinforcement and silica sol as precursor. Micro-structure and morphology, thermal insulation properties, thermostability,mechanical property were studied by SEM,plane wave thermal conducticity, the quartz radiation heating system,univeral testing muchire. The result indicated flexible SiO2 wave-transparent aerogels composites has greater dielectric properties,the dielectric constant could be adjusted in 1. 28 to 1. 39, the tanδ is less than 0. 005,the thermostability is greater than 1 100℃,the thermal conductivity is less than 0. 02 W/ ( m·K). It also has better mechanical property, which could make the flight vehicle work normally of communication,telemetry and control in severely flying environment.