The utility model relates to an energy-saving system of a power plant, comprising a steam inlet system of a small steam turbine, an open-cycle cooling water system, a condensed water recovery system, a shaft seal and lubricating system of the small steam turbine and a condenser vacuum-pumping system. A draught fan can be used as a booster fan of the power plant, and the small steam turbine drives the draught fan. By adopting the system, the power consumption rate of the power plant can be greatly reduced, the purpose of energy consumption of the power plant is realized and the production cost of the enterprise is reduced.