In this study, the thiol-functionalized resin (PMA-SH) was prepared directly by a one-step reaction of polymethyl acrylate resin (PMA) and 1,2-ethanedithiol, and it was applied to the adsorption of Pb 2+ , Ni 2+ , and Hg 2+ in aqueous solution. The effects of initial concentration, temperature, contact time, and electrolyte on the adsorption of Pb 2+ , Ni 2+ , and Hg 2+ were investigated. At 308 K, the saturated adsorption capacity of PMA-SH on Pb 2+ , Ni 2+ , and Hg 2+ is found to be 0.94, 0.88, and 0.41 mmol/g, respectively. In addition, the experimental adsorption data were consistent with the Redlich-Peterson model and pseudo-second-order kinetic model. Overall, PMA-SH exhibited good reuse performance as well as excellent adsorption performance for Pb 2+ , Ni 2+ , and Hg 2+ .