The invention discloses a water level controller with overvoltage protection, which is characterized by comprising a system power supply, an overpressure protection circuit, a water level probe circuit, a high-low water level detection and recognition control circuit, an execution relay, a water pump, an indicating light and the like. The water level controller has a function of disconnection protection during overvoltage output and protects a water pumping motor when a mains supply is in an overvoltage state; only two wires are needed for the detection wires from the high-low water level control circuit to a water tank of a water tower; the water level is detected by using the conductivity of water, and the water level of the water tank of the water tower is controlled to be between a high detection point and a low detection point; and when the water level is lower than a low water level detection point, the motor is started for pumping water, and when the pumped water level is lifted to the high water level detection point, the water pump is turned off. The invention can eliminate the defects that a contact point is burned and the motor is damaged due to intermittent on/off of arelay caused by water level fluctuation. The invention has simple and reliable circuit, high sensitivity, convenience, practicability and easy popularization.