and gas turbines flue gas was explored. Based on the basic theory of combustion, detailed calculations were conducted on the theoretical airvolume, flue gas volume, burner nozzle velocity and other parameters of coal - fired boiler combustion after mixing with gas turbineflue gas. A coupling combustion technology scheme of gas turbine flue gas and coal - fired boiler was proposed. The influence of fluegas coupling on the combustion characteristics of coal-fired boiler was analyzed using full-scale numerical simulation technology.The numerical simulation results indicate that after flue gas coupling,the tangential diameter increases. As the initial temperature of pulverized coal flow increases, the volatile releases earlier, and the pulverized coal ignites earlier,The temperature of the boiler furnace decreases, and the heat absorption of the water wall decreases. The NO emission at the furnace outlet increases from 222. 1 mg/ m to229.5 mg/ m, and the burnout rate decreases from 98.91% to 96.9%. Based on numerical simulation results, the energy consumption ofthe whole plant after flue gas coupling was analyzed, it can be concluded that although the coal consumption of boiler power generation increases by 2.0 g/ kWh,the waste heat utilization efficiency of gas turbine flue gas has increased from about 80% to about 93%, representing a reduction of 10.98 g/ kWh in the coal consumption of boiler power generation, so the energy consumption of the whole plant has decreased. The results indicate that coupling combustion technology of coal-fired boilers and gas turbines is feasible. After flue gas coupling,the gas turbine flue gas replaces most of the secondary air, significantly reducing the air flow through the air preheater, resulting in a significant decrease in the heat of the air preheater and a significant increase in the flue gas temperature. It is necessary to add a waste heatutilization device after the air preheater.