Polyaniline (PANI) coated iron tetroxide was used to prepare of Fe₃O₄@PANI magnetic adsorption material for the adsorption of iodine in water. The morphology and properties of the composite before and after adsorption were characterized by SEM, TEM, FT-IR, XRD, VSM, XPS and Raman, and the adsorption mechanism of the composite was explored. The effects of adsorption time, iodine solution concentration, adsorption temperature and regeneration on the adsorption properties were also investigated. The results show that iodine is bound to benzene ring, quinone ring and nitrogen atom of quinone ring structure unit of polyaniline when coated with ferric tetroxide adsorbed I₂. The adsorption process of I₂ by Fe₃O₄@PANI is endothermic and spontaneous, which accords with the quasi-second-order kinetic model and the Langmuir isothermal adsorption model. At 303.15 K, the theoretical maximum adsorption capacity is 1 777.13 mg/g. After the adsorbent is desorbed with ethanol and recycled for 3 times, the adsorption rate reached 44.22% of the first adsorption rate.