The invention relates to a water-saving controller, which relates to a water-saving device. The water-saving controller comprises a control circuit board provided with a power switch, wherein a power transformer is connected to 220 V power input through the power switch, and supplies a set of 24 V power sources for the control circuit board; signal ends of two sensors of the control circuit board are connected with one end of a water closet tank sensor and one end of a water storage tank sensor respectively; the other end of the water closet tank sensor and the other end of the water storage tank sensor are connected with common ends of the sensors of the control circuit board; three output signal ends of the control circuit board are connected with one end of each of a solenoid valve, a suction pump and a flushing pump respectively; and the other ends of the solenoid valve, the suction pump and the flushing pump are all connected with output common ends of the control circuit board. The water-saving controller has the advantages of concise structure, stable performance, high control sensitivity and good water-saving performance.