Although various NOx removal technologies have been commercialized, NOx emissions are still so high that they cannot meet the newest standard and endanger the eco-environment and human health. Meanwhile, some NOx reduction technologies suffer from high costs. Recently, a cheap and pending technology called gas-fired coal preheating has surfaced again. This method introduces hot flue gas to heat a coal stream to high temperatures before the coal stream is injected into a utility boiler for combustion, thus resulting in a reduction in NOx. Considering the complex mechanisms during preheating, the effect of the preheating parameters, including temperature, residence time, excess air ratio, and coal type, are studied in a laboratory-scale drop-tube furnace in detail. Meanwhile, by means of Chemkin coupled with the mature NOx reduction mechanisms of GRI-mesh3.0 and Dagaut, as well as a CPD model, a detailed kinetics analysis on NO removal, including the migration and transformation of hydrocarbons and nitrogenous compounds during PC preheating, is performed. The research provides intuitive guidance, in practice, and a new scientific interpretation, in theory, for NOx reduction during PC combustion with preheating.