[en] At present, research on the surface chemical properties of uranium minerals is very scanty, which restricts the research progress of uranium ore flotation process. On this account, the pitchblende is selected as the object of study in this paper, because it is widely distributed in uranium deposits. By means of microscopic observation, infrared spectroscopy, XRD test, Zeta potential test and XPS test, a systematic study on surface characteristics of pitchblende is carried out. The research results shows that, the(110) direction of the crystal is the preferential fracture surface of pitchblende, and the ratio of U and O on the surface is about 1 : 2. The two kinds of unsaturated bonds on mineral surface combine with H⁺ and OH^- and produce compounds. The compounds are differing in ionization degree and bond energy. Therefore, the Zeta potential of pitchblende in pure water is negative when the pH value is between 2 and 11. The pitchblende exists in four characteristic absorption bands. On the surface of pitchblende, U is mainly in the form of U0₂, Th is mainly in the form of ThO₂, and Pb is mainly in the form of Pb and PbO. (authors)