The reaction characteristics of different mixing ratios of coal/char to NO reduction were investigated under the conditions of relatively low O-2 concentration at 1073-1203 K. The inlet NO concentration ranges used in this study were 270600 ppm. The results showed that even a small increase in O-2 concentration can significantly accelerate the reaction process, but the increase in O-2 concentration also made the total efficiency of NO reduction gradually decline. Besides, under the presence of O-2, with the increase of temperature, the reduction efficiency of char was gradually reduced, whereas the reduction efficiency of coal was gradually increased. Under the condition of the 25%/75% coal/char mixing ratio, the NO reduction in the earlier stage and the NO release in the later stage seemed to reach a balance; thus, the total reduction efficiency did not change significantly with the change of temperatures. Meanwhile, in the subsequent combustion and emission, characteristics of residues after NO reduction were also investigated under the O-2-free condition and it can be concluded that the combustion reactivity of the residues of different samples was the best for coal samples and the worst for char samples.