Abstract: In order to reveal the oxidation-dissolution mechanism of molybdenite in the flotation process, the products were characterized by means of XPS, SEM, EDS and Raman spectroscopy, and the solution properties was detected through conductivity, pH value and ion concentration. The results show that there are different oxidation ability of molybdenum and sulfur between the polar surface and the non-polar surface of molybdenite, and the sulfur is more easily oxidized. The solubility of oxidation products of different elements on the polar surface of molybdenite are also various, and the oxidation product of sulfur on the polar surface is easier to dissolve. During the oxidation-dissolution process of molybdenite, the pH value of the solution decreases firstly and then increases, and the solution conductivity the remains unchanged after reaching 0.51 S·m^-1. The oxidation products of the sulfur on the polar surface of molybdenite are fully dissolved when the oxidation-dissolution time is 0.5 h, which causes the concentration of SO₄^2- in the solution reaches 56.8 mg/L and the relative content of sulfur on the polar surface reaches a minimum of 24.92%. In view of the fact that the conductivity of the solution remains basically unchanged and the relative content of Mo-O bond almost unchanged when the oxidation-dissolution time is greater than 2.0 h, the oxidation products of the molybdenum on the polar surface of the molybdenite attain solution equilibrium. The research can provide a theoretical basis for realizing the control of molybdenite hydration capacity in the flotation process, and it also has certain reference significance for improving the separation efficiency of molybdenite.