The present invention relates to a fire extinguishing composition which generate fire extinguishing substance by high temperature sublimation; the fire extinguishing composition comprising a fire extinguishing material which, in a heating process, can sublimate and release a fire extinguishing substance with fire extinguishing properties; the content of the fire extinguishing material is at least 80 wt %. When the fire extinguishing composition is in use, a pyrotechnic agent as a heat source and a power source; and the purpose of fire extinguishing is achieved by: igniting the pyrotechnic agent, generating a large quantity of fire substance from the fire extinguishing composition in the use of high temperature produced by burning pyrotechnic agent, and the fire substance sprays out together with the pyrotechnic agent. When compared with traditional aerosol fire extinguishing systems, gas fire extinguishing systems and water type extinguishing systems, the present invention can provide a more efficient and safer fire extinguishing composition.