In order to remove MnO-4 from wastewater effectively, Fe3O4-RGO was synthesized by hydrothermal method. SiO2 was introduced to modify Fe3O4 via the emulsion-gel method, and the adsorption performance of the material was enhanced by grafting EDTA. Finally, a magnetic nano-manganese removal agent Fe3O4@SiO2@EDTA-RGO was obtained. The morphology, crystal structure and magnetic properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and magnetic recovery experiment. The effects of adsorption time, adsorbent dosage and initial concentration on MnO-4 adsorption were investigated. The results showed that the adsorbent had good crystal structure and regular morphology. Fe3O4@ SiO2, with an average particle size of about 108 nm, was uniformly loaded on the surface of RGO without obvious agglomeration. When the adsorption time was 80 min, the dosage of adsorbent was 0.5 mg and the initial concentration of MnO-4 solution was 3 mg/L, the adsorption effect was the best, and the adsorption reaction conformed to the pseudo-second -order kinetic model. The removal rate of MnO-4 was still as high as 85.23% after 5 cycles of use.