Abstract: Optimum reaction conditions for oxidation of acid fuchsin by bromate ions （BrO<SUB>3</SUB><SUP>-</SUP>）in hydrochloric acid medium with sodium chloride as catalyst were studied.Maximum absorption wavelength of decoloring solution lines at 576 nm with a reaction apparent molar absorptivity of 1.31×10<SUP>5</SUP> L/（mol·cm）,and mass concentration of BrO<SUB>3</SUB><SUP>-</SUP><SUP> </SUP>in the range of 0.12~0.75 mg/L conforms to Beer′s law.The method has been applied in determination of micro BrO<SUB>3</SUB><SUP>-</SUP>in KBr chemical reagents and satisfactory results were obtained as well. 