The invention relates to a method for synthesizing a vinyl sulfone compound. The vinyl sulfone compound has a chemical molecular formula shown in the description, wherein R1 is one selected from H, a straight-chain alkyl electron-donating group, a nitro electron withdrawing group, F, Cl and Br, and R2, R3 and R4 each is selected from H and straight-chain alkyl. The synthetic method comprises the steps of adding an inorganic base in an organic reaction solvent by taking an aryl sulfonyl chloride compound and a tertiary amine compound as reaction substrates and taking eosin Y as a catalyst under the action of visible light, carrying out a reaction for 1 to 3 hours at the temperature of -5 DEG C to 5 DEG C under the irradiation of an LED (light-emitting diode) lamp, carrying out water washing treatment, extraction and drying after the reaction ends, then, carrying out reduced-pressure distillation to remove the organic solvent, and then, carrying out thin-layer chromatography and column chromatography separation, thereby preparing the vinyl sulfone compound. Compared with the prior art, the method provided by the invention has the advantages that the steps are simple, the reaction conditions are mild, the controllability is good, the consumption of metal complexes is avoided, the reaction cost is reduced, and the method is pollution-free to environments.