Abstract: In order to remove Cu(II) from the liquid phase efficiently, the amine-modified silica aerogel (NG) was prepared by co-condensation method using tetraethyl orthosilicate as raw material and 3-aminopropyltriethoxysilane as amino agent. The effects of pH, ionic strength, time, temperature and other factors on the removal of Cu(II) by NG were systematically investigated. The adsorption mechanism of Cu(II) on the NG was analyzed by combining adsorption kinetics model, adsorption isotherm model, adsorption thermodynamics and site energy distribution theory. The results demonstrate that the adsorption capacity of Cu(II) increase with pH value from 3.00-6.00, and the adsorption is inhibited by the addition of ionic strength at the range of 0-0.08 mol/L. The outer-sphere complexes formed by Cu(II) and NG are confirmed by using FTIR analysis. Furthermore, the adsorption equilibrium is achieved within 8 h, and the adsorption process mainly go through boundary layer diffusion, intra-particle diffusion and chemisorption. The adsorption process is best fitted with the pseudo-second-order model and Freundlich model. The increase of temperature is beneficial to promote the adsorption reaction of Cu(II), and the maximum adsorption capacity reaches to 130.45 mg/g. The adsorption process is endothermic and entropy increasing spontaneous reaction. The energy distribution show that Cu(II) is preferentially adsorbed on the high-energy adsorption sites on NG and then occupied low-energy adsorption sites. Overall, the adsorption mechanism is mainly attributed to the electrostatic interaction and the outer-sphere complexation.