Abstract: A new catalytic kinetic potentiometric method for the determination of trace manganese is Propose. The propose method is based on the catalysis of manganese to the oxidation of crystal violet by KIO₄. A crystal violetion selective electrode is used to indicate the variation of Crystal violet concentration.The linear range of the method is 7～74μg/L of Mn (Ⅱ).This method has been used to determine the manganese content in standard steels,the results obtained are dose to the standard values.