The invention provides a steam hot aerosol fire-extinguishing composite which contains 30-80wt percent of oxidant, 10-60wt percent of fuel additive and 2-30wt percent of cohesion solidification molding auxiliary agent. The oxidant can be one or more of the following substances: potassium salt, strontium salt, ammonium salt, magnesium salt, nitrocellulose and nitroglycerin; the fuel additive can be one or more of the following substances: azos, azoles, amino-guanidine nitrate, sodium bicarbonate, melamine, cyanoguanidine, carbamide, hexamine, triaminoguanidine nitrate, olefin, saccharose, aluminium powder, magnesite powder and magnesium-aluminium alloy power; the cohesion solidification molding auxiliary agent can be one or more of the following substances: phenol formaldehyde resin, ethoxyline resin, glycidyl azide, urethane rubber, hydroxyl-terminated polybutadiene, polyisobutylene, acetyl tributyl citrate, carboxymethyl cellulose, polyvinyl alcohol phenolic resin and acrylic resin. The invention also provides a fire extinguishing method and a fire extinguishing device adopting the composite. The invention has strong fire extinguishing capacity and fewer hazardous materials and can be applied to different places.