Objective To establish a dual-indicator catalytic kinetics spectrophotometric method for the detection of trace amounts of iron(Ⅲ). The test was based on the remarkable catalytic effect of iron(Ⅲ) on the oxidation of methylene blue by hydrogen peroxide in hydrochloric acid medium. Method Determining the absorbance at 610 nm and 666 nm for catalytic and uncatalytic systems with the dual-wavelength catalytic spectrophotometric method to detect trace amount of iron(Ⅲ). The best experimental condition and the reaction mechanism were studied. Results The linear range was 0.2～3.0 μg/25ml. The detection limit was 9.24×10-¹¹ g/ml. Conclusion This method was sensitive, stable and easy operated. The practical use on the detection of trace iron in tea samples was satisfactory.