The invention relates to an aqueous film-forming foam fire extinguishing agent based on a C4 gemini fluorinated surfactant and belongs to the technical field of fire protection consumable items. The structural formula of the C4 gemini fluorinated surfactant is shown in the specifications, wherein n is equal to 2-6. The aqueous film-forming foam fire extinguishing agent which is prepared with anion C4 gemini fluorinated surfactant with the fluorocarbon chain length being 4 carbons as a core component does not contain PFOA/PFOS and is economical and environmentally friendly. The prepared aqueous film-forming foam fire extinguishing agent can form a water film restraining oil evaporation on the oil surface, reduce the flame temperature, cut off fuel feeding and meanwhile isolate fuel and air, rapid fire extinguishing is achieved by comprehensively using cooling, isolating and stifling mechanisms, and the aqueous film-forming foam fire extinguishing agent has the beneficial effects of being high in fire extinguishing efficiency, high in speed, good in anti-combustion property and sealing capability, long in storage time and the like.