Abstract: Taking a 650 MW supercritical opposed wall-fired boiler as the research object,the distribution characteristics of the flue gas components near the water wall of the side wall under different nozzle types and nozzle heights were analyzed by numerical simulation methods. A circular slot nozzle with height of h = 40 mm is selected to design a combination schemes,which can mitigate the hightemperature corrosion of side walls. And the effect of the scheme was evaluated by the whole furnace simulation. The results show that: the simulated high CO concentration area of the side wall coincides with the actual corrosion location under the original condition without adding the wall wind; With the same installation position,nozzle height,air speed and air flux,the reduction rates of the high-temperature corrosion ratio ε of the circular slot nozzle,the vertical slot nozzle,and the horizontal slot nozzle are 4.23%,2.42%,and 5.70%,respectively,and the circular slot nozzle not only has a good anticorrosive effect,but its O_2 distribution characteristics are also more suitable for engineering applications; With the same nozzle type,installation position and air flux,the relative velocity between the nozzle stream and the main stream plays a leading role in the attenuation of the O_2 concentration at the upstream nozzle stream; The intensity of the main stream and its scouring area to the nozzle stream plays a leading role in the attenuation of the O_2 concentration at the downstream nozzle stream. The declines in the high-temperature corrosion ratios ε of the four nozzles h = 30,40,50,and 60 mm are 5.62%,4.23%,3.87%,3.20%. In engineering applications,in order to maintain a good anti-corrosion effect,and avoid the excessive loss of flow resistance and waterwall wear caused by highspeed airflow,it is recommended to select the nozzle with h = 40 mm. The designed combination scheme of near-wall air can form an intersecting O_2 curtain in most side wall area,the proportion of areas prone to high temperature corrosion is reduced to 12.88%,and the scheme has little impact on combustion and pollutant emissions.