The invention provides an alarm water tank, which overcomes the problems that the current water tanks are easily overflow, so that floor and various furniture can be damaged due to wetting, and electric shock is easily happed. The alarm water tank is composed of a tank body, a water leakage aperture, a button, an alarm, and a graduation line. The alarm water tank is characterized in that the waterleakage aperture, the button and the graduation line are arranged at the tank body, the water leakage aperture is connected with the button, and the alarm is connected with the tank body. The alarm water tank has the advantages of simple structure, strong practicality, and easy popularization.