Manganese (Mn) is an important element in environmental geochemistry. In many natural aquatic systems, high concentrations of manganese are present with organic and inorganic matters. The oxidation of Mn(II) in aqueous systems has been extensively studied. But inorganic and organic matter effects on oxidation have not been fully clarified. It is clear that Mn(II) oxidation in the presence of inorganic and organic matter runs differently.