The invention relates to a mercaptan removal and lye regeneration device and a method for gasoline light fractions. The mercaptan removal and lye regeneration device for gasoline light fractions comprises a static mixer, a liquid film alkaline wash reactor, a lye coalescence remover, a lye oxidation separation tower and a liquid film extraction contactor. The mercaptan removal and lye regeneration device and the method for gasoline light fractions have the advantages that pre-alkaline washing is used for removing hydrogen sulfide and phenol, so that the investment is low; the two-stage liquid film alkaline wash reactor and the alkaline wash process are utilized, so that the mercaptan in products can be guaranteed to be below 10 parts per million (ppm), no free lye is carried, and the copper sheet corrosion and water-solutbility acid base detection can be guaranteed to be qualified with no water wash needed; the oxidation rate of mercaptan sodium in the lye is high, two-phase perturbation emulsification is quite slight, and more than 60% of generated disulphide can be separated and recycled; the content of the disulphide in the regenerated lye can be guaranteed to be no more than 100 ppm, and the regenerated lye cannot be re-extracted into products when used for removing mercaptan in a circulation mode; the total sulfur in products can be guaranteed to be stable and not rise without replacing the lye frequently, and compared with other processes, the discharge amount of alkaline residues is reduced by more than 50%.