Abstract: Achieving controllable structure and uniform coating is the key for the preparation of core-shell magnetic composite materials. The exchange of Na⁺ with Fe²⁺ and Fe³⁺ on the surface of sulfonic polystyrene (PSS) was completed by ion exchange method. The PSS surface loaded Fe₃O₄(PSS@Fe₃O₄) magnetic composite particles was obtained with alkaline existed. The maximum encapsulation rate of Fe₃O₄ was calculated by weighing method. The magnetic properties were analyzed by vibrating sample magnetometer (VSM). The chemical composition and microstructure of PSS@ Fe₃O₄ magnetic composite particles were analyzed by XRD, ATR-FTIR and SEM-EDS. The results show that the saturation magnetization of PSS@Fe₃O₄ magnetic particles increases with the increase of Fe²⁺/Fe³⁺ concentration. The maximum saturation magnetization of PSS@Fe₃O₄ magnetic particles is 7.51 emu/g which owned the obvious magnetic response. Fe₃O₄ is evenly coated on the surface of PSS, and the maximum coating rate is 8.3 wt%. The PSS@Fe₃O₄ composite particles are expected to be applied in magnetorheological, medical and waste water treatment fields.