Abstract: Based on the titrimetry with reduction of ammonium vanadate by titanous chloride for the determination of micro-amount of uranium, some operation procedures in sample digestion, filtration and washing, reduction-oxidation and titration were improved. Samples were digested with H₃PO₄-HCl-H₂O₂ at low temperature. After centrifugation, filtering, reduction of UO²⁺₂ with Ti³⁺, oxidization of excessive Ti³⁺ by NaBrO₃ and further oxidization of trace impurities with low valence by urea-NaNO₃, uranium in the sample solution in a small volume (10 mL) was titrated with ammonium vanadate. The end point of the titration was very clear. Detection limit of the method for uranium was 0.001% and precision was 0.05%~ 0.07%RSD. The method provides the advantages of simple operation, high efficiency and is suitable for the determination of 0.001%~0.01% uranium in ore and slag samples.