The total specific surface area of quantitative dry powder is small, the mass of single particle is large, the sedimentation rate is fast, and the decomposition rate is slow when heated, resulting in its low ability to capture free radicals, so the fire extinguishing ability is limited, which limits the use range of dry powder fire extinguishing agent to a certain extent. The particle size of dry powder fire extinguishing agent is directly related to its fire extinguishing efficiency. The larger the critical particle size of the fire extinguishing component, the better the fire extinguishing effect. Therefore, it is an effective way to improve the fire extinguishing efficiency of dry powder fire extinguishing agent to prepare ultrafine fire extinguishing powder that can be uniformly dispersed and suspended in the fire space, ensure the activity of fire extinguishing component particles, and reduce the amount of fire extinguishing agent used per unit space.