A disclosed high-temperature-resistant sealant is prepared from the following raw materials in parts by weight: 6-10 parts of bamboo charcoal fiber, 4-8 parts of hollow bead, 8-14 parts of nitrile butadiene rubber, 10-20 parts of EVA thermoplastic elastomer, 6-12 parts of paraffin oil, 3-8 parts of graphene, 4-9 parts of isocyanate, 5-8 parts of aluminium hydroxide, 2-6 parts of terpene resin, 4-8 parts of gas-phase white carbon black, 7-11 parts of diaryl secondary amine, 7-14 parts of polysulfide rubber, 5-10 parts of zinc oxide, 10-20 parts of epoxy resin, 20-30 parts of acrylate emulsion, 8-16 parts of chitin, 7-9 parts of ethanol, 5-11 parts of kerosene, 5-8 parts of illite powder and 4-8 parts of attapulgite. The provided high-temperature-resistant sealant is excellent in waterproof performance and good in high-temperature resistance and flame resistance.