The EDTA functionalized magnetic nano-particles (MNPs-EDTA) as a novel magnetic nano-adsorbent have been prepared by a simple one-pot method for the removal of Cu(II) from aqueous solution. Factors affecting the adsorption of Cu(II) on MNPs-EDTA, such as contact time, temperature, pH, salinity, and initial concentration of Cu(II), were investigated. The studies on the adsorption revealed that the adsorption process obeyed the pseudo-second order kinetic model, the determining step might be chemical sorption and the adsorption equilibrium could be achieved in 5min. Among the various isotherm models, the experimental data for the adsorption of Cu(II) followed the Langmuir isotherm best and the maximum adsorption capacities was 46.27mgg −1 at pH 6.0 and 298K. Thermodynamic parameters declared that the adsorption process was endothermic and spontaneous. The removal efficiencies of Cu(II) were over 98.3% and inappreciably influenced by the water matrix. In addition, the adsorption–desorption studies indicated that MNPs-EDTA had a high stability and good reusability.