The invention relates to the technical field of coal desulfurization, in particular to a method for large-particle-size coal desulfurization through microwave-assisted halogen elementary substance, and aims to solve the technical problem that an existing current large-particle-size coal desulfurization method has a low desulfurization rate. The method sequentially comprises the following steps: S1, crushing raw coal, and performing screening to obtain a coal sample of which the particle size is greater than or equal to 1 mm; S2, preparing a reaction reagent: dissolving a halogen substance intowater to form a stable solution to obtain a desulfurization reaction reagent; S3, mixing the coal sample obtained in the S1 and the reaction reagent obtained in the S2 according to a mass ratio of the reaction reagent to the coal sample of 2:1 to 20:1 to obtain a mixed reactant; S4, performing radiation on the mixed reactant obtained in the S3 under microwaves, wherein the microwave frequency is300-2500 MHz, the microwave radiation power is 300-1000 W, the microwave treatment time is 0.5-10 min, and the pressure is normal pressure; and S5, filtering a coal sample obtained in the S4, and performing washing to obtain a low-sulfur coal sample.