Abstract: The muscovite samples were characterized by component distribution chart, ζ potential, SEM-EDS and XPS spectra etc. and then the mechanism of Cu²⁺ on the flotation behavior of muscovite in sodium oleate system was investigated. The result showed that when the pulp pH value was 12, the concentration of sodium oleate 9.20×10^-4 mol/L and the concentration of Cu²⁺ 1.18×10^-4 mol/L, the muscovite recovery rate can reach 55.70%, where the effect of activated muscovite was best. And after that continuing to increase Cu²⁺ concentration, the activation effect would decrease. The main reason for Cu²⁺ to improve the floatability of muscovite was that the Cu(OH)₄^2- adsorbed on the muscovite surface interacted with oleate ions in solution and then formed hydrophobic copper oleate. Moreover, when the concentration of Cu²⁺ was 1.18×10^-4 mol/L, the zeta potential of the muscovite surface reached -4.08 mV, leading to increase of the muscovite surface charged local area, so the concentration of Cu²⁺ can enhance the electrostatic adsorption of oleate ions on the muscovite surface, and Cu²⁺ can also increase the reaction probability of oleate ions with reactive Al and Si on muscovite surface, which also increases the floatability of muscovite. The reason for the reduction of Cu²⁺ activation is that: excessive Cu²⁺ can gradually weaken in the electrostatic adsorption of oleate ions muscovite surface charged region, and excessive Cu²⁺ can consume part of collector, it can also reduce the probability of collecting agent by reaction with mineral surface.