The present disclosure relates to a polymerizable surfactant with reducibility and a preparation method thereof. The acid anhydride is reacted with a long-chain fatty alcohol to obtain an intermediate of an anhydride monoester, and then the obtained intermediate is reacted with the hydrochloride of dimethylaminohalogenated alkane, and a polymerizable surfactant with reducibility is obtained by post-processing. The polymerizable surfactant can not only play a role as a reactive emulsifier and copolymerize with monomers to obtain a soap-free emulsion, but also form a redox initiation system with peroxide, and conduct redox emulsion polymerization at room temperature. The soap-free emulsion synthesized by the polymerizable surfactant synthesized can greatly reduce the energy consumption in production, and can carry out one-step emulsion polymerization at normal temperature or low temperature to obtain an environment-friendly emulsion with a branched structure, thereby obtaining coatings with excellent water resistance, weather resistance, and impact resistance.