Abstract: The influence of streptomycin mycelial residue （SMR） blended with coal on the combustion characteristics and NO_x emission was investigated by numerical simulations with a 330 MW subcritical tangentially fired boiler as the research object. The results indicated that the mixing ratio and blending mode of SMR had little influence on the velocity field in the furnace, and a good tangent circle could be formed under different working conditions. However, the combustion temperature field, gas component distribution and NO_x generation characteristics were significantly affected. The adoption of the diagonal addition of SMR nozzles from between the primary and secondary air nozzles did not change the combustion parameter distribution characteristics, but it weakened the effect of concentration and lightness separation, resulting in a significant increase in NO production. The injection of SMR with primary air from the A and C layer nozzles had a significant effect on the combustion characteristics, resulting in high NO concentrations at the furnace outlet. The spraying of SMR from the F layer nozzle with primary air had the least effect on the pulverized coal combustion as well as the best effect on NO control.