The invention relates to a fluorine-containing surfactant and a preparation method thereof. The fluorine-containing surfactant has a compound structural formula shown in the formula (I). The preparation method has simple processes and a low cost. The amphoteric fluorine-carbon surfactant has excellent emulsification effects, can be used as a fluorine-containing polymer polymerization assistant, can be used as an emulsifier in paper, leather and fabric finishing agents and can be combined with a metal surface decontamination cleaner. The amphoteric fluorine-carbon surfactant is easily compatible with other surfactants, can be processed to form different fluorine-containing surfactant stock solutions, can be used in various fields, is especially suitable for an aqueous film-forming foam extinguishing agent in the field of fire protection and is mainly used for foam stabilization and film-forming spreading.