The graphene oxide (GO) functionalized by Fe₃O₄@SiO₂@CS-TETA nanoparticles, Fe₃O₄@SiO₂@CS-TETA-GO, was firstly fabricated in a mild way as a novel adsorbent for the removal of Cu(II) ions and methylene blue (MB) from aqueous solutions. The magnetic composites showed a good dispersity in water and can be conveniently collected for reuse through magnetic separation due to its excellent magnetism. When the Fe₃O₄@SiO₂@CS- TETA-GO was used as an absorbent for the absorption of MB and Cu(II), the adsorption kinetics and isotherms data well fitted the pseudo-second-order model and the Langmuir model, respectively. Under the optimized pH and initial concentration, the maximum adsorption capacity was about 529.1 mg g⁻¹ for MB in 20 min and 324.7 mg g⁻¹ for Cu(II) in 16 min, respectively, exhibiting a better adsorption performance than other GO-based adsorbents reported recently. More importantly, the synthesized adsorbent could be effectively regenerated and repeatedly utilized without significant capacity loss after six times cycles. All the results demonstrated that Fe₃O₄@SiO₂@CS-TETA-GO could be used as an excellent adsorbent for the adsorption of Cu(II) and MB in many fields.