[en] Method for X-ray fluorescence analysis of complex ores (uranium-molybdenum-zirconium ones) for element content is proposed. The method permits increase noise stability due to unambiguous separation of an analytical line of the element determined against the background of interfering radiations. For this purpose the medium studied is irradiated by a flux of X-ray quanta, and the flux of characteristic radiation of the element determined is determined according to the results of measuring radiation fluxes in two energy intervals of secondary radiation spectrum. The first interval includes amplitude distributions of analytical lines of determined and interfering elements, the second interval is placed inside the first one and corresponds to the analytical peak of the determined element. The width of the first energy interval and the location of its boundaries are determined so that the ratio of pulse counting rates (K) recorded in the first and in the second intervals in the absence of the determined element remained stable in the case of variation in the concentrations of interfering elements. The content of the element determined is found from the difference Δ=N₂-kN₁ where N₁ and N₂ are pulse countuing rates in the first and second energy intervals