In 2% ethylenediamine（en） Solution （pH 11.5）, by using single sweep Polarography, Mn（en）,3,2+, Complex has a Sensitive Polarographic adsorptive wave. Ep=-1.8V（VS. SCE）. There is a linear dependence of wave height on manganese concentration over a range of 5×10,-8,M—6×10,-6,M. 3 times of Co,2+, 10 times of Pb,2+,、Bi,3+,、In,3+, 30 times of Fe,2+,(or Fe,3+,)、Cr,3+, 50 times of Ni,2+,、Zn,2+, and at least 100 times of other Common ions do not interfere the determination of manganese. This method has been applied to the determination of trace amounts of manganese in hair and tap water. The properties and mechanism of this adsorptive wave have been studied and disscussed.