The invention discloses thioether compounds and a synthetic method thereof. The structure of the thioether compounds is shown in formula I, wherein X and R1-R10 are defined in the specification. According to the synthetic route, a product is finally synthesized from 9H-Xxanthene-9-one through hydrogenation, thio-etherification, hydrogen removal and alkylation. The thioether compounds can have a certain trigger action in radical polymerization and can be subjected to a reversible coupling-cleavage reaction with chain propagation radicals, so that the chain propagation radicals form dormant species, and polymerization shows certain controllability. Meanwhile, compared with reagents used in the traditional 'active'-controllable radical polymerization system, the compounds have the advantages of being nontoxic, odorless, colorless and free of metal ions, have better solubility without additional ligands and the like, and have better application prospect in the field of radical polymerization.