Abstract: Based on the catalytic effect of vanadium on the discoloring reaction of light green SF oxidized by H2O2in medium of sulfuric acid, a new method for the determination of vanadium(Ⅴ) was proposed. The optimum determination condition and kinetic parameters have been investigated. The detection limit is 5.2 ng/L with linear range of 0.0～40 ng/mL for vanadium(Ⅴ). The method has been applied to the determination of trace vanadium in water and tea samples with satisfactory results.