The invention discloses an extinguishing agent. The extinguishing agent is formed by mixing and stirring strong hydrophobic solid particles and aqueous solution at high speed, wherein the strong hydrophobic solid particles are one type or more of magnesium hydroxide particles, silicon dioxide particles, calcium carbonate particles, talcum particles, aluminium oxide particles, aluminium hydroxide particles, zinc borate particles, zinc oxide particles, iron sesquioxide particles, titanium dioxide particles, montmorillonite particles, hydrotalcite particles, coal ash particles, diatomite particles, mica particle, attapulgite particles and zeolite particles after hydrophobic modification. The extinguishing agent disclosed by the invention is nontoxic, environmental pollution is less, and secondary loss caused by strong flowability of water can be avoided while playing the advantages of the water as the extinguishing agent and reducing the using amount.