Flaky graphene oxide (GO) prepared by the improved Hummer method was used as a carrier and template to load cobalt ions. Then, nano-metal Co/graphene magnetic composite adsorption material (Co/rGO) was prepared using in situ reduction method and was applied to adsorb and remove Cu2+ to provide the guidance for the synthesis and application of remover with efficient and reusable copper ion. The experimental results showed that Co/rGO composite materials had super paramagnetism, and could be easily separated by magnets as well as be oscillating dispersed without magnetic field. Co/rGO composite materials had stable adsorption and desorption properties for Cu2+. The maximum adsorption capacity for Cu2+ could reach 117.5 mg/g under experimental conditions and the adsorption balance could be achieved within 5 min, which was far superior to its raw material GO with the adsorption capacity of 27.6 mg/g in 60 min. In this work, the key factors including the amount of NaOH addition, the type of complexant, and the type of solvent on the morphology and distribution characteristics of Co particles on rGO carrier were systematically investigated. The adsorption effects for Cu2+ of composite materials under different synthesis conditions were compared. The properties of Co/rGO composite materials prepared in preferred conditions were characterized by FT-IR, XRD and SEM. The results showed that the adsorption process of Cu2+ by nano-Co/rGO magnetic materials was more consistent with Freundlich model and belonged to multilayer adsorption. The adsorption enthalpy ΔH was 17.81 kJ/mol, and the equilibrium constant of adsorption reaction Kθ was 3.65 at room temperature. When the initial concentration of Cu2+ was 39.22 mg/L, the desorption rate exceeded 93%, and initial value of adsorption capacity remained at 94% after five adsorption/desorption cycles. The residual concentration of Cu2+ in the solution after each adsorption always met the requirements of cobalt electrolyte for the removal of impurity copper ions (5 mg/L) or GB 8978-1996 level 3 (2 mg/L) of comprehensive sewage discharge, which was expected to play a role in related fields.