Abstract: A type of ion exchange resin containing thiol groups directly bonded on the aromatic ring via a series of reactions with crosslinked polystyrene microspheres was synthesized, and its characteristics for Hg²⁺ adsorption were described. Resin characterization using FT-IR indicated that thiol groups were successfully grafted on the resin surface. Elemental analysis results showed that the thiol groups in the resin were 2.89 mmol/g. Hg²⁺ adsorption capacities were dependent on the solution pH. The adsorption of Hg²⁺ was found to be weak with pH 1, so the thiol resins can be regenerated with acid washing. The best adsorption behaviors of the resins to Hg²⁺ were observed with pH ranging from 2 to 7. The adsorption isotherms of Hg²⁺ over thiol resins were measured. Increasing adsorption temperature enhanced the adsorption of Hg²⁺, with sorption capacity up to 14.500 mg/g. Hg²⁺ adsorption behaviors could be well described using the Langmuir adsorption model. The kinetics of Hg²⁺ adsorption onto the thiol resins could be well described by a pseudo-second order kinetic model. When used in the decontamination of water containing 1 mg/L of Hg²⁺, the final Hg²⁺ mass concentration was 0.003 mg/L.