Abstract: A large amount of uranium-containing wastewater produced in the nuclear industry circulation chain will cause damage to human health and ecological environment. Therefore, efficient treatment of uranium-containing wastewater is an important part of ensuring the sustainable development of the nuclear industry and human ecological security. Polyethyleneimine (PEI) functionalized composite aerogel (MGO/PEI) was synthesized by self-assembly of graphene oxide as a precursor and used to remove U(VI) from aqueous solution. The effects of different PEI dosage, stability, pH value, time, U(VI) concentration and temperature on the removal of U(VI) were investigated. The results showed that the adsorption behavior was accorded with the pseudo-second-order kinetic model and the Langmuir isothermal adsorption model at 298 K and pH=6, and the maximum adsorption capacity was 1027.01 mg·g⁻¹. The thermodynamic constants indicated that the adsorption of U(VI) by MGO/PEI was a spontaneous endothermic process. XPS analysis showed that the removal mechanism was mainly due to the surface complexation of amino and oxygen-containing functional groups with U(VI).