The invention discloses a pollution-free water-based fire extinguishing agent. The pollution-free water-based fire extinguishing agent is formed through mixing and stirring of the following components of, by weight, 34 parts of a hydrocarbon surfactant, 6 parts of ammonium polyphosphate, 20 parts of coconut oil alkyl betaine, 4 parts of cationic hydroxyethyl cellulose, 14 parts of dodecyl imidazoline, 2 parts of a fluorinated surfactant, 8 parts of urea, 7 parts of sodium chloride, 7 parts of polysorbate 20, 16 parts of an antifreeze agent, 15 parts of ethylene glycol and 53 parts of deionized water. The pollution-free water-based fire extinguishing agent can extinguish fires of the class A and the class B and can also be stored and attenuated with water for application in the environment with the temperature higher than -40 DEG C, and the defect that a traditional water-based fire extinguishing agent cannot be stored or attenuated with water for application in the environment with the temperature lower than -10 DEG C is overcome; in addition, the pollution-free water-based fire extinguishing agent is definitely safe in the processes of production, transportation, storage, application and the like and does no harm to human bodies; after the pollution-free water-based fire extinguishing agent is used, no residue exists; and after exceeding the time limit, the pollution-free water-based fire extinguishing agent can be used as an oil dirt cleaning agent and is environmentally friendly and harmless.