Abstract: Experiments were conducted in a fluidized bed with I.D.of 81mm and height of 1600mm to investigate NO _x emissions from incineration of waste water,which contains hexamethylenediamine of 4.5% and dilute HNO ₃ of 1.25%.The result shows that decomposition products of dilute HNO ₃ water solution are NO and NO ₂.NO is the main product,which represents more than 90% of total NO _x.The conversion ratio of HNO ₃ converted to NO _x is about 95%～96%.The results of incinerating organic waste water in a temperature range from 800℃ to 950℃ shows that,under non-staged combustion condition,the de-NO _x ratio is only about 46%～61% at oxygen concentration of 11%.Staged combustion was adopted to further decrease NO _x emission.The experimental data indicate that the NO _x emission can be reduced very efficiently,the de-NO _x ratio is increased up to 86%-93%.It was found that the presence of hexamethylenediamine is positive for reduction of NO _x emission.950℃ is the optimal operation temperature for incineration of the examined waste water,concerning the NO _x reduction.