A fire extinguishing composition generating fire extinguishing substance through chemical reaction of ingredients at high temperature, wherein: the fire extinguishing composition comprises a flame retardant, an oxidant, a reducing agent and an adhesive; contents of each ingredient are: the flame retardant: 50 wt % to 90 wt %; the oxidant: 5 wt % to 30 wt %; the reducing agent: 5 wt % to 10 wt %; the adhesive: 0% to 10 wt %. In a usage of the fire extinguishing composition, a pyrotechnic agent is adopted as a heat source and a power source; and the purpose of fire extinguishing is achieved by: igniting the pyrotechnic agent, and the oxidant and the reducing agent in the fire extinguishing composition are reacted to generate the in the use of high temperature produced by burning the pyrotechnic agent. by burning the pyrotechnic agent, so as to implement fire extinguishing. Different from the traditional aerosol generating agent, there is no external heat source, and the composition itself does not burn. Compared with the traditional aerosol generating agent, the fire extinguishing composition of the present invention is more efficient and safer.