Through an analysis of the current operational economic indicators of a 330 MW subcritical coal-fired unit and field research on the operational status of on-site equipment and systems， the unit's actual coal consumption rate and the primary factors affecting its operational economics were determined. On this basis， the quantitative impacts of these factors on the economic indicators of the unit were further calculated， revealing the energy loss distribution and primary causes. The direction and priorities of future energy conservation and consumption reduction were clarified， and targeted technical approaches and implementation schemes were proposed. Meanwhile， the energy consumption level of the unit after various retrofits was predicted and analyzed. The research results can provide a reference for optimal operation， equipment maintenance and technical renovation of power plants.