Emergy analysis and exergy analysis as scientific analysis are widely used to assess the development of industrial systems. This article attempts to combine the characteristics of emergy and exergy analysis in order to evaluate the sustainable development level of three thermal power plants. It establishes an exergy/emergy indicator to amend the system yield ratio, while introducing emergy waste ratio and economic indicators to calculate the economic, environmental, and social benefits of thermal power plants. The results of the three plants' sustainability evaluation show that the revised indicators are suitable for evaluating the sustainable development of the thermal power plant.