Abstract: The production of ⁹⁹Mo that use low-enriched uranium as irradiation target instead of high-enriched uranium is an inevitable trend. However, the composition of the fission system may be changed with low enriched uranium target, which can affect the separation and extraction process of ⁹⁹Mo. In this paper, the extraction behaviors of Mo(Ⅵ) from nitric acid solution by bis(2-ethylhexyl) phosphate in sulfonated kerosene were studied in present of U(Ⅵ) with high concentration. Especially, the effects of different concentrations of Mo(Ⅵ), extraction time, extractant concentration, concentration of nitric acid, temperature and the other major elements (included Cs(I), Zr(Ⅳ), Y(Ⅲ), Nd(Ⅲ), Al(Ⅲ)) on extraction were investigated. The results show that the extraction behaviors of Mo(Ⅵ) by bis(2-ethylhexyl) phosphate in sulfonated kerosene are similar in different concentrations. The good extraction efficiency could reach by 10% bis(2-ethylhexyl) phosphate in sulfonated kerosene when the phase ratio is 1.The distribution ratio of Mo(Ⅵ) decrease with the increasing of concentration of nitric acid when the c₀(HNO₃)≤ 2 mol/L, but it have nearly no effect on extraction of Mo(Ⅵ) by nitric acid when the concentration of HNO₃ is more than 2 mol/L. The extraction reaction is exothermic and spontaneous at ambient temperature because the ΔH and ΔG are negative. Additionally, no remarkable influence on the distribution ratio of Mo(Ⅵ) by bis(2-ethylhexyl) phosphate in sulfonated kerosene by U(Ⅵ) and the other major elements could be noted, while, there is a high selectivity for seperation of Mo(Ⅵ) from Y(Ⅲ), Nd(Ⅲ), Al(Ⅲ) by using P₂₀₄.