Abstract: Based on the technology of desulfurization, self-denitrification and selective non-catalytic reduction（SNCR） denitrification in circulating fluidized bed（CFB）, the emission of air pollutants from CFB units was studied. The combustion model, the pollutant generation and removal model in CFB units were established, and the key state variables affecting the emission of pollutants were analyzed. Results show that the established models of SO₂ and NO_x emission of CFB units can fit the actual operation data well, and have certain prediction effect and strong model universality. The combustion of carbon affects the reduction atmosphere in the furnace, which significantly affects the reduction of NO_x. The amount of active limestone and furnace temperature is the main factors affecting the curing reaction between SO₂ and active limestone, while relatively high furnace temperature and less active limestone stock will both increase the concentration of SO₂ emission, but the higher the temperature is, the lower the level of NO_x emission is.