The relationship between the constituents and the heating value of the coal is complicated.Currently there is no unified method in the energy loss analysis in coal-quality index for coal-fired boilers.The generally adopted method,of which the limitations are apparent,is to analyze the individual index of the coal quality.Study shows that the converted moisture,converted ash and the converted hydrogen are at once the quality index of the coal and the quantitative index of the combustion products which are closely related to the heat loss of the boiler.Starting from a formula for boiler heat loss,this article proposes a method for energy-loss analysis using the converted constituents of the coal with examples of calculation and analysis.Simple and practical as it is,this method can be an alternative for colleagues of other power plants in energy-loss analysis.