The invention discloses a fire extinguishing agent. The fire extinguishing agent is prepared from the following raw materials of, by weight, 3-8 parts of fluorinated alkyl betaine, 10-20 parts of fatty alcohol ether sodium succinate, 15-25 parts of lauramidopropyl dimethylamine ethyl lactone, 0.5-2.5 parts of organic silicon quaternary ammonium salt, 5-15 parts of lauryl betaine and 5 parts of dodecyl betaine, compounding 40-55 parts of ethylene glycol and glycerol, compounding 5-20 parts of diethylene glycol monobutyl ether and n-butyl alcohol, 5-10 parts of urea, 0.03-0.08 part of xanthan gum, 0.5-1 part of sodium alginate, 2-10 parts of ethylene diamine tetraacetic acid or ethylenediamine tetraacetic acid or sodium citrate, 0.1-1 part of triethanolamine and 40-50 parts of water. The fire extinguishing agent has the beneficial effects that no toxic and harmful substances are generated in production and use, during hand, face and other skin contact experiments, the skin does not haveany uncomfortable reactions, the mouth wash experiment proves that the corrosion with extremely low damage to human mucosal tissues is avoided, the storage tank and fire-fighting facilities are prevented from being damaged and the residue is very easy to clean after protected articles are extinguished, meanwhile, the fire extinguishing agent can be automatically degraded and is especially suitable for protecting petroleum and chemical products.