Due to the increasing development of thermal power plants with fossil fuels, Optimizing the combustion process in boilers and combustion chambers to reduce the amount of environmental pollutants is of great importance. In this paper, the effect of the temperature of the intake air into the combustion chamber and its effects on the production of nitrogen oxides and soot emissions have been studied. The results show a decrease in combustion temperature, Flame temperature is reduced and nitrogen oxides emissions are also reduced. Also in the air optimal flow obtained, due to the complete combustion of fuel and high-temperature combustion chamber, nox was also the maximum and with the increase in air flow and temperature efficiency is reduced again. Comparison of numerical results obtained from the analysis and simulation of the current situation boiler data shows good agreement.