<p>Thermal properties and NO emission behaviors during the oxy-fuel decoupling co-combustion of Shenmu coal(SM) and pine-sawdust (PS) were investigated. The effects of pyrolysis temperature, combustion temperature, PS blending ratio, oxygen concentration, and N₂/CO₂ atmospheres on NO release characteristics were systematically examined. In the conventional combustion of PS/SM, two NO distinct peaks were observed, corresponding to volatiles combustion and char combustion. The NO release curve during decoupling combustion exhibited a single peak because the flue gas released after volatiles combustion passes through the char layer, where further reactions took place. Compared with the conventional combustion process, the NO emissions during decoupling combustion was reduced by 24.4% for SM, 44.4% for 40PS60SM and 7.1% for PS, respectively. The NO emissions from SM, 40PS60SM and PS steadily increased with rising combustion temperature. The experimental NO release values were consistently lower than the theoretically calculated values, suggesting the presence of a synergistic effect between SM and PS that further suppressed NO formation during decoupling co-combustion. The NO reduction mechanisms were elucidated, and a theoretical foundation was thus provided for the efficient, low-emission co-utilization of coal and biomass.</p>