In order to get close-packed hydrophobic molecular monolayer, surface modification of ilmenite was carried out with cupric ions. As it was found by zeta potential and XPS measurement, the cupric ions modification occurs via ion exchange, metal hydroxides adsorption, and redox processes. After modifying by cupric ions, ilmenite surface properties became more active and the adsorption amount of a-hydroxyoctyl phosphinic acid (HPA) increased. As expected, the flotation behaviour of ilmenite improved. XPS measurements verified the ability to establish a covalently attached HPA on the surfaces of ilmenite after Cu(II) activation. The findings of this study will provide a fundamental basis for strengthening flotation.