Abstract: In the process of high-speed flight, the temperature of the aircraft rises rapidly. The sealing material between the aircraft cabin should not only have excellent high-temperature resistance, but also have a low thermal conductivity to assist in blocking the heat transfer between the cabin, and have excellent mechanical properties to prevent it from being damaged. Used hollow ceramic microspheres as aggregates, added phenolic resin and phosphate curing system to prepare organic/inorganic hybrid high-temperature resistant and tough composites. The composites were subjected to high-temperature treatment to study the changes of the composites before and after the high-temperature treatment. The compressive strength, compression deformation ability, microstructure and composition changes of the composites before and after the high-temperature treatment were characterized by mechanical performance test, SEM observation, XRD and FT-IR. In addition, the high-temperature resistance performance of the composites was tested by flame combustion. The overall results show that the prepared composites have high compressive strength and excellent toughness. The macro morphology of the composites is not affected by the high-temperature treatment at 1000℃ for 600 s, which indicates that the composites have high thermal stability. And the thermal conductivity test results show that the increase in the content of hollow ceramic microbeads, the addition of phenolic resin and the high-temperature treatment all cause the thermal conductivity to decrease, and the lowest thermal conductivity is as low as 0.16 W/(m·K).