Abstract: A chitosan magnetic nano composite material CSB@Fe₃O₄ NPs was prepared by combining modified chitosan with magnetic Fe₃O₄ nanomaterials, which had the advantages of large specific surface area, high selective adsorption, and easy separation. Using a simulated water sample containing 9 heavy metal elements including Cr, Cu, Zn, As, Se, Ag, Cd, Sb, and Pb as the research object, the 9 heavy metal elements were determined by inductively coupled plasma mass spectrometry （ICP-MS） and the adsorption conditions were optimized to explore the adsorption effect of CSB@Fe₃O₄ NPs on heavy metal elements in industrial wastewater. As shown by the results, under the conditions of adsorption temperature of 20 ℃, the initial mass concentration of heavy metal elements not exceeding 5 mg·L⁻¹, 10 mg of CSB@Fe₃O₄ NPs amount, pH 6.0 of solution, and ultrasound oscillation for 120 min, the above 9 heavy metal elements could be effectively adsorbed. The adsorption rates of 9 heavy metal elements in 3 actual industrial wastewater were tested. Except for the adsorption rate （34.4% ） of Cr element in No.3^# water sample, the adsorption rates of the rest were in the range of 71.9%‒94.2%.