Incineration is the most promising method of sludge treatment at present. However, a large amount of NOx, SOx and other polluting gases are generated during the burning process, which increases the load on the flue gas desulphurization and denitrification. Thereare many studies on the mechanism of nitrogen oxide emissions during the combustion of fuels such as coal and biomass, but studies onthe combustion reactions and pollution emissions of elemental nitrogen from sludge are rarely carried out. Four common amino acid model compounds (glycine, glutamic acid, phenylalanine and tryptophan) in sludge were selected and chemical calculations were conductedby the density functional theory DFT/ B3LYP method with 6-31G basis groups. The different bond lengths and Mulliken Boujou numbersof the amino acids were analyzed and compared, using relatively easy to break bonds as initiating bonds for pyrolysis. Weaker chemicalbonds were selected for breaking at each step of the reaction pathway, gradually optimizing the calculations until all the nitric oxide (NO)was isolated. Three nitrogen migration reaction paths were designed for glycine, and five nitrogen migration reaction paths were selectedfor glutamic acid, two nitrogen migration reaction paths were selected for phenylalanine, and with total of seven reaction paths were considered for tryptophan. The products of each path contain NO, and the path with the least thermal absorption from the outside world is chosen as the best reaction path for amino acids by comparing the calculated thermodynamic parameters. The best nitrogen migration pathfor glycine requires 339.21 kJ/ mol of heat absorption from outside, 304.92 kJ/ mol of heat absorption from outside for glutamic acid,324.27 kJ/ mol of heat absorption from outside for phenylalanine, and the best reaction path for tryptophan nitrogen migration does notrequire heat absorption from outside. A multi-channel reaction network for the migration and transformation of nitrogen-containing components during sludge combustion is constructed based on the reaction pathways of four amino acids, and the migration and transformationreaction mechanism of typical nitrogen-containing compounds in sludge are clarified, providing necessary basic data and theoretical basisfor sludge recycling and harmless utilization.