Abstract: The quality of coal has a certain impact on the fluctuation of coal calorific value. The combustion of a single coal type will lead to a large difference in coal calorific value during the combustion process. Therefore, research on controlling the difference in coal calorific value in thermal power plants with multiple coal types combined and co fired is carried out. Design a method for correcting the stratified calorific value of coal, by stratifying the coal and adjusting it based on the calorific value characteristics of each layer, in order to improve the accuracy of coal calorific value. Research on the calculation method of thermal power plant coal calorific value difference considering the combination and blending of multiple coal types, and establish a calorific value difference calculation function by comprehensively considering factors such as coal type ratio and combustion efficiency. By monitoring the difference in calorific value in real-time and adjusting the coal blending ratio, combustion parameters, and boiler operation mode based on its size and direction, dynamic control of calorific value difference can be achieved. Through practical applications, it has been proven that the new control method can effectively reduce the difference in coal calorific value, improve the operational efficiency and economic benefits of thermal power plants.