A stream condenser vacuum improving energy-saving control system can greatly improve the vacuum of a steam condenser, which is characterized by comprising a refrigerating system, a chilled water main pipe system, a vacuum pump work water system, a vacuum pump work water bypass system, a chilled water spraying system and a water level regulating and discharging system, wherein the refrigerating system can respectively cool a plurality of parallel vacuum pump work water systems and chilled water spraying systems through the chilled water main pipe system, the vacuum pump work water system and the chilled water spraying system of a plurality of units can be cooled through different chilled water main pipe systems, a plurality of vacuum pump work water systems of the same unit can independently work or respectively commonly work with the same chilled water spraying system of the unit, thereby respectively forming an independent steam condenser vacuum improving system, a plurality of vacuum pump work water systems and chilled water spraying systems of the same unit share one water level regulating and discharging system, and a plurality of vacuum pump work water systems of the same unit can share one vacuum pump work water bypass system.