Abstract: Fe₃O₄@MgO nanocomposites were prepared by two-step chemical precipitation method. The adsorption properties of nanocomposites for Pb²⁺ were investigated. The results show that the prepared composites have super paramagnetism and high stability, and the saturation magnetization and the initial temperature of oxidation are 58.07emu/g and 125 ℃, respectively. The as-obtained composites have excellent adsorption performance for Pb²⁺ with the maximum adsorption capacity of 711.5 mg/g, and the adsorption equilibrium can be reached within 50 min. The adsorption process well followed the pseudo-second-order kinetic model and Langmuir isotherm model.