Coal-fired unit efficient subcritical system

The invention discloses a coal-fired unit efficient subcritical system. According to the coal-fired unit efficient subcritical system, heat consumption can be reduced through changing the parameters of main steam and reheat steam. Under rated conditions, the pressure of main steam generated from a boiler is not higher than 18.5MPa, the temperature of the main steam is higher than 540 DEG C and smaller than or equal to 623 DEG C; the pressure of the main steam entering a high-pressure cylinder of a turbine from a main steam pipeline is lower than 17.5MPa, the temperature of the main steam is higher than 538 DEG C and is lower than or equal to 620 DEG C; steam discharged from the high-pressure cylinder goes back to the boiler and is re-heated so as to form reheat steam; the pressure of the reheat steam is lower than 5.21MPa, and the temperature of the reheat steam is higher than 540 DEG C and lower than or equal to 623 DEG C; and the pressure of the reheat steam entering a middle-pressure cylinder of the turbine is lower than 4.96MPa, and the temperature of the reheat steam is higher than 538 DEG C and is lower than or equal to 620 DEG C. Based on the parameters of the main steam and reheat steam which are improved in an optimized manner, the coal-fired unit efficient subcritical system of the invention can effectively improve the efficiency of a coal-fired unit and save energy, and can operate safely and stably, and can assist in reducing environmental pollution.