Abstract: Graphene oxide(GO) has attracted extensive attention in the field of water environment treatment due to its large specific surface area and rich oxygen-containing functional groups. Graphene oxide was modified by carboxylation. The effects of solution pH, ionic strength, reaction time and initial concentration on the adsorption performance of carboxylated graphene oxide were systematically studied. It was found that carboxylated graphene oxide has strong adsorption capacity for Nd³⁺. The adsorption rate of Nd³⁺ on carboxylated graphene oxide is very fast, and most of Nd³⁺ can be adsorbed in 10 min. The adsorption equilibrium can be reached in 30 min, which is accord with the pseudo-second-order kinetic model. The adsorption performance is almost not affected by ionic strength. The adsorption isotherm is in accordance with Langmuir model, which indicates that the adsorption process is monolayer chemical adsorption. The study of Nd³⁺ adsorption behavior by carboxylated GO materials provides a new choice for the separation of rare earth elements in water treatment.