Abstract: Most of flue gas is washed by wet spraying to achieve efficient removal of pollutants in engineering projects. However,it is found that there is a large amount of aerosol produced during this process,which makes the tail gas unable to meet emission standards. Up to now,the relevant researches focus on the formation mechanism and corresponding control methods of SO_3 acid mist and sulfate aerosol,and there is no report or research focuses on the phenomenon of nitrate aerosol in some applications of ozone deNO_x technology. Therefore,through the establishment of ozone deNO_x system,the Gasmet flue gas analyzer was used to measure the gas components and concentration,the aerosol particle size distribution sampler and ion chromatography were used to measure the concentration of the nitrate aerosol. An experimental study on the formation mechanism and control of nitrate aerosol was carried out. The results show that the nitrate aerosol concentration is positively correlated with the initial NO concentration,which increases from 7.06 mg/m~3 to 18.66 mg/m~3 as the NO concentration increases from 200×10~(-6) to 400× 10~(-6). When O_3/NO molar ratio is 1.0,the presence of NH_4~+ in the slurry causes the nitrate aerosol concentration to increase. When the N_H4~+ concentration increases from 2 g/L to 4 g/L,the nitrate aerosol concentration remains at 8 mg/m~3,but the average particle size increases. Additionally,the aerosol concentration decreases with the increase of O_3/NO molar ratio without NH_4~+ addition. However,when 2 g/L NH_4~+ was added into the slurry,the aerosol concentration increases dramatically from 7.06 mg/m~3 to 161.94 mg/m~3 as the O_3/NO raises from 1.0 to 1.6. The addition of reducing additives X in the slurry significantly reduces the aerosol concentration with the maximum aerosol suppression efficiency of 47.7%. This method has a certain industrial application prospect as a nitrate aerosol suppression technology in the ozone deNO_x process.