The layered double hydroxides (LDHs) were in-situ prepared by hydrolyses of copper, magnesium, and aluminium ions with sodium hydroxide solutions for removing copper ions from wastewater. The effects of medium pH, magnesium/copper molar ratio, reaction temperature and time on the removal efficiencies of copper ions were investigated. The results show that the removal efficiencies are significantly affected by the medium pH, and the removal efficiencies are more than 99% in the range of pH 8.0～11.0. Other factors have slight effects on the removal efficiencies. X-ray diffraction analyses of these prepared LDHs indicate that their layers are composed of copper, magnesium, and aluminium ions, and the copper ions are removed at the crystal formation stage of these LDHs. These Cu/Mg/Al-LDHs are formed by stepwise hydrolyses from aluminium to copper to magnesium ions, with the suitable pH value being 9.0.