Industrial wastewater treatment has emerged as a significant global challenge. Although physical adsorption offers advantages such as effective contaminant removal and operational simplicity, it often entails high consumption of adsorbent materials and elevated costs. Because of its superparamagnetic, small particle size, large specific surface area and easy recovery characteristics, Fe₃O₄ shows broad potential in the field of adsorption, but its application alone still has some limitations. This paper aims to review the preparation and application of magnetic composites based on Fe₃O₄ as a green and efficient adsorbent in wastewater treatment, in order to deal with the current problems of high cost and difficult recovery of adsorption materials. The main synthesis methods for magnetic activated carbon, magnetic cyclodextrin, and magnetic cellulose composites were introduced, followed by an overview of their use in the adsorption of heavy metals and organic pollutants. Additionally, an analysis was conducted on the advancements in the application of magnetic separation and regeneration technologies. The results indicate that Fe₃O₄ composite material has good performance in adsorption efficiency, environmental protection and cost control. Fe₃O₄ composites have shown unique advantages as potential adsorbents. It is suggested that Fe₃O₄ composite adsorption materials with low cost and high adsorption capacity should be further developed to promote its transformation from laboratory to engineering application.