Abstract: An amino-functionalized nano-Fe₃O₄ magnetic composite material (NH₂-nFe₃O₄) was synthesized by one-pot solvothermal method. The NH₂-nFe₃O₄ was characterized by EA, XRD, FTIR, TEM and VSM. Its application for adsorption and degradation of pentachlorophenol (PCP) was investigated. The results show that the NH₂-nFe₃O₄ has an average size of about 20 nm, with the saturation magnetization intensity of 56.8 emu/g. The adsorption capacities were investigated by adsorbing the PCP from aqueous solutions. Thermodynamic studies suggest that the adsorption processes fit the Freundlich isotherms well. The adsorption capacity of NH₂-nFe₃O₄ is found to be 899.2 mg/g when the initial concentration of PCP at 1000 mg/L. The adsorption kinetic studies show that the adsorption processes reach the equilibrium within 5 min and the kinetic data are well fitted to the pseudo-second-order model. The post-adsorbed material was added to Fe³⁺-H₂O₂ system. In situ degradation of PCP via Fenton-like reaction under visible light can be realized. The results indicate that at pH 3.0—8.0, the degradation of PCP with loading concentration at 6.25—120.0 mg/g can be reached to almost 100% within 5 min. NH₂-nFe₃O₄ can be reused after regeneration. It is a potential effective and reusable material for adsorption and degradation of PCP.