Abstract: Utilizing the sol-gel method, this study presents the fabrication of carbon nanotubes/organic silicon resin (CNT/OSR) aerogels and quartz fibre-reinforced CNT/silicon (QF/SC) composites incorporating varying proportions of multi-wall carbon nanotubes. The investigation focuses on discerning the influence of CNT content on the microstructural, thermal, and wave absorption properties of silicone aerogels and their composites. Results demonstrate the favorable compatibility of modified CNT with silicone resin, facilitating the establishment of micro-conductive and thermal conductive pathways. Remarkable enhancement in thermal stability of the modified resin is observed, notably with a 111.1℃ increase in T_d10 when the CNT mass fraction constitutes 15wt% of the silicone resin. Moreover, the thermal conductivity of QF/SC composites spans from 0.054 to 0.075 W/(m·K), with a maximum rear temperature of 145.1℃ attained after 600 s exposure at 1000℃. Furthermore, the introduction of carbon nanotubes substantially augments the dielectric properties of QF/SC composites, leading to peak reflectance and effective bandwidth measurements within the range of 8-18 GHz, registering at -29 dB and 3 GHz, respectively. This research anticipates fostering novel applications in aerospace science and industry.