Solid propellant for the rocket motors contains large amount of ammonium perchlorate (AP) as an oxidizer. To recover AP from unserviceable or waste rocket propellants, water-washout of AP from the propellant was proven to be safe and environmental-benign process. However this process produces high concentration of AP solution by using water jet. Since AP was known to cause the thyroid gland disorder, it should completely recycled or destructed in a closed system. One of the treatment method for the AP solution is incineration. In this research, we used submerged quench incineration system to destroy the AP solution generated from the water-washout process. When the AP solution is sprayed into the incinerator, NOx and HCl were produced as main gases. A De-Nox system comprising by wet oxidation and reduction units were used to remove NOx gases. When the 19.6wt% AP solution was injected to the incinerator at a feed rate of 9.4 kg/hr, NOx concentration measured at the exit of the incinerator and reduction tower was 974ppm and 48ppm, respectively with O2 12% correction showing NOx reduction rate as 95.1%. Hydrogen chloride resulted from AP decomposition was absorbed to the circulation water in the quencher. The quench water becomes acidic rapidly with incineration time. Perchlorates measured from the flue gas at stack was zero which indicates that no perchlorates were discharged to the atmosphere.