In order to analyze the influence of a pulverized coal furnace co-firing with biomass gas on the operation performance of the coupled boiler,a biomass gasification coupled coal-fired boiler system model was built based on a 660 MWe coal-fired boiler and a 30 t/h biomass gasifier. At rated working conditions,three types of biomass,namely pine wood,wood chips,and sludge,were selected for gasification process research. The biomass gases obtained on the optimal gasification condition were fed into the boiler for mixed combustion,the influence law on boiler operation and combustion products generation from different biomass gases co-firing was researched. The results show that the gasification heat efficiency of biomass can reach more than 90% at the best air-fuel ratio. Compared to the pure coal combustion conditions,the furnace combustion temperature of the coupled system decreases,with a highest drop value of 9.43 ℃. The combustion mixed with biomass gas makes the boiler efficiency slightly decrease,but the biomass utilization efficiency of the coupled boiler system can still reach 84% above. In addition,the multi-fuel combustion can reduce CO2 emissions,and the CO2 cut from co-combustion with pine-gas is the largest of all three material,with the value of 2.62×105 t/a. The amount of NOx reduced in the coupled system is significantly related to the furnace combustion temperature and the CH4 concentration in biomass gas,with a maximum drop value of 167.16 mg/m3 from blending a wood chip gas. The SOx mass concentration is relevant to the composition of biomass gas and the lowest value is from co-firing a pine gas,with a drop value of 330.22 mg/m3,compared to the pure coal combustion.