Abstract: Magnetic polymer adsorbent with semi-interpenetrating network structure was prepared by water solution free radical polymerization using KH570 modified magnetic nanoparticles and N, N-methylene diacrylamide as crosslinking agent as crosslinking agents, and the structure and properties of the adsorbent were studied. Both magnetic nanoparticles, KH570 modified magnetic nanoparticles and magnetic polymer adsorbents have characteristic diffraction peaks of magnetic Fe₃ O₄. Magnetic nanoparticles and KH570 modified magnetic nanoparticles have significant Tyndall effect and magnetic responsiveness. Magnetic polymer adsorbent has uneven surface with many micropores and ravines, approaching heavy metal ions adsorption balance at 60 min, reaching heavy metal ions adsorption equilibrium at 90 min with adsorption capacities of Cu²⁺, Cd²⁺ and Pb²⁺ of 152 mg/g, 131 mg/g and 450 mg/g, respectively.