Previous studies on ammonia/ coal co-firing have focused on numerical simulations and small-scale test furnaces, while large-scale test furnaces are mostly used for point-case tests of technical feasibility. In this paper, a detailed study of the emission and processdistribution characteristics of ammonia/ coal co-firing was carried out in a 50 kW one-dimensional self-sustained combustion experimentalfurnace under different operating conditions. In order to fully understand the contribution of ammonia and coal to NO production duringthe combustion process, a series of experimental studies were carried out for pure ammonia combustion. Air-staged combustion greatly reduces NO emissions from ammonia/ coal co-firing combustion. With ammonia co-firing ratios ranging from 10% to 90%, NO concentrations varie from 170 to 215 mg/ m3, which are at the same level with pure coal combustion. The optimal burnout air ratio is maintainednear 38%. Further increasing the burnout air ratio will not further reduce NO emissions, but will lead to negative effects such as inadequate combustion. Pure ammonia combustion employing air-staged combustion technology can manage the exported NO concentration, butits stability is significantly worse than that of ammonia/ coal co-firing, and ammonia is prone to escape when the oxygen concentration inthe operation is low. Ammonia/ coal co-firing may not only solve the problems of ammonia combustion difficulties and excessive NO emissions, but it can also minimize CO2 emissions from coal combustion, making it a very attractive technology route for future energy growth.