Specifics of measurements of elemental composition of uranium ores, which have natural radioactivity, using Wavelength Dispersive X-ray Fluorescence spectrometer S 8 Tiger were examined in the work. It is shown that own radioactivity of uranium ores, resulting from presence in them Pb, Bi, Po, Th, Pa, Ra and U isotopes and can influence on the results of determination of certain elements' content. The model of correction by intensity with empirical alpha-coefficients is proposed to use for matrix effects correction during analysis of content of P, S, Mg, Al, Si , K, Ca. It is shown, that such approach, in comparison with standard software Spectra Plus of spectrometer S 8 Tiger, allows reduce relative error of measurements in 10-100 times. An analysis of possible spectral interferences of analytical lines of studied elements and additionally discovered in X-ray spectra peaks of Ba, Ni, Sr and Pb was done. It is shown, that using appropriate matrix effects correction the influence of spectral overlaps may be neglected.