Abstract: The combustion of fossil fuels produces substantial greenhouse gases and atmospheric pollutants including NO and SO?, which inflict severe damage on the ecological environment. As a high-energy and high-pollution sector, the cement industry urgently needs low-carbon, clean, and efficient combustion technologies. This study focuses on ammonia-coal co-combustion in a 5000 t/d cement rotary kiln, investigating the effects of injection positions (swirl, axial, central, and coal air ducts) and blending ratios (0%, 10%, 20%, 30%) on combustion characteristics and pollutant emissions.Results indicate that ammonia injection via the coal air duct achieves optimal comprehensive performance: NH? fully mixes with air to form a homogeneous "ammonia-coal-air" mixture before entering the combustion zone, with the temperature peaking at 1972 K (16.5 m of the kiln) and remaining 1325 K at the kiln tail, while the outlet NO concentration is only 554 ppm (much lower than other ducts). The blending ratio of the coal air duct significantly regulates the kiln’s temperature field and emissions of NO/CO2. The high-temperature zone presents a mallet-shaped distribution; as the ammonia ratio increases, the peak temperature decreases from 1970 K (0%) to 1945 K (30%), and the cement clinker calcination length shortens from 14.93 m to 11.9 m. The outlet NO rotary kilns. concentration rises from 321 ppm (coal-only) to 555 ppm (20% ammonia) due to the enhanced NH3-O2 reaction outweighing NH3’s NO reduction effect, whereas CO2 concentration drops from 13.2% to 10.4% (20% ammonia).This study clarifies the regulatory mechanisms of ammonia injection parameters on the kiln’s temperature field and pollutants, providing a theoretical basis for developing carbon-nitrogen reduction technologies in cement