Abstract: The ethylenediaminecobalt(II)cations can not only bind NO but also activate oxygen molecules in aqueous solutions.NO is absorbed and oxidized simultaneously so that relatively water insoluble NO is oxidized to soluble NO_2 which can then be fixed as NO~~-__2 and NO~~-__3.A possible mechanism for these reactions was suggested and the feasibility was demonstrated by some illustration experiments.The influences of oxygen,pH and different desulfurization agent on the removal of NO are investigated.(According) to the experimental results,oxygen in the gas phase is favorable to the removal of NO.The(optimal) pH of solution is 12.86 in the presence of oxygen.The addition of CaO and Ca(OH)_2 in solution can achieve higher removal efficiency of NO that was sustained longer than others.The optimal dosage of CaO is 1.8 g/L.