Abstract: A new kinetic fluorimetric method was proposed for the determination of trace molybdenum. The method is based on the fluorescence quenching of acridine yellow by the reaction product of hydrogen peroxide and potassium iodide with Mo(Ⅵ) as a catalyst in phosphoric acid solution. The detection limit is 0.15 μg/L. T he linear range of determination is 0.16～2.4 μg/L.The method suffers on interf erences from more than 20 foreign ions. The method has been applied to the deter mination of trace molybdenum in tea, green bean and mineral water samples with s atisfactory results.