[en] Interfering ions are the main influencing factors to time resolved fluorescence (TRF) analyses of trace uranium. The influence of H⁺ , Fe³⁺ and NO₃^- are studied in this paper. The fluorescence intensity of uranyl fluorescent complex is greatly affected by nitric acid. The fluorescence are completely quenched when the concentration of nitric acid is 0.075 mol/L. The concentration and lifetime of fluorescent complex are reduced by the addition of H⁺. The fluorescence intensity is also affected by Fe³⁺ and NO₃^- because of the absorption of exciting light. (authors)