Abstract: Utilizing surplus electricity from renewable energy sources such as wind power and photovoltaic power to produce green hydrogen through large-scale water electrolysis, and further synthesizing green ammonia using green hydrogen as zero carbon fuel for co-firing power generation in coal-fired boilers, this technological route is very feasible. It can effectively solve the problem of renewable energy power consumption and help the clean and low-carbon transformation and upgrading of the coal-fired power industry. The technology route for green ammonia synthesis and ammonia co-firing combustion power generation in coal-fired boilers is introduced in detail. Currently, major power generation groups in China are vigorously carrying out the project approval and construction of green ammonia co-firing demonstration projects. A summary of the current development status of green hydrogen production from renewable energy and green ammonia synthesis technology from green hydrogen is provided. PEM electrolysis hydrogen production technology and Haber-Bosch synthetic ammonia technology are the mainstream technologies that can be commercially applied. This paper discusses the progress of ammonia co-firing combustion technology research and industrial application experiments for coal-fired boilers at home and abroad, and focuses on the literature review of NO_x generation mechanism and the influence of coal type, ammonia co-firing ratio, combustion air rate, ammonia injection position, temperature, air classification and other factors on NO_x emissions. The effects of ammonia co-firing combustion on the flue gas volume and composition, SO₂ and SO₃ emission concentrations, and acid dew point are analyzed based on engineering cases. The research results show that ammonia co-firing combustion in coal-fired boilers will significantly change the flue gas volume and composition. As the proportion of green ammonia co-firing gradually increases from 0% to 50%, the wet flue gas volume and exhaust humidity gradually increase, while the dry flue gas volume and the outlet flue gas SO₂ and SO₃ emission concentrations gradually decrease. The acid dew point temperature calculated using the three commonly used acid dew point calculation formulas first slightly increases and then slowly decreases, and the overall change in acid dew point temperature is not significant. This indicates that ammonia co-firing combustion in coal-fired boilers has little effect on the acid dew point of flue gas.