The invention discloses a 
nitrogen oxide treatment system and a method thereof, the 
nitrogen oxide treatment system comprises a 
gas mixing adjusting area, a 
plasma excitation area, an SO2 absorption area and an 
NOX reduction area which are communicated in sequence, the 
plasma excitation area, the SO2 absorption area and the 
NOX reduction area are sleeved with an insulating and heat-insulating shell, the 
gas mixing adjusting area is provided with a gas inlet, and the 
NOX reduction area is provided with a gas outlet; a gas flow rate adjusting 
pipe for adjusting the gas 
inlet flow rate of the gas inlet is arranged in the 
gas mixing adjusting area, and the gas mixing adjusting area is further communicated with a gas inlet 
pipe; an insulating tube is sleeved in the 
plasma excitation area, 
discharge copper plates are oppositely arranged in the insulating tube, and a porous 
drying plate is detachably arranged behind the area where the insulating tube is located; a porous absorption plate is arranged in the SO2 absorption area; a porous first catalytic reaction plate, a porous second catalytic reaction plate and a porous 
drying plate are sequentially arranged in the NOX reduction area. According to the treatment device and the treatment method thereof, 
nitrogen oxides can be efficiently treated, and SO2 poisoning and inactivation are not prone to occurring.