An AC voltage detection circuit includes a conversion module, a comparison module, and a prompt module. The conversion module connects to an AC power source and converts the AC voltage provided by the AC power source to an AC current, and then converts the AC current to a direct current (DC) voltage reflecting the AC voltage. The comparison module is connected to the conversion module, and compares the DC voltage with a first predetermined voltage and a second lesser predetermined voltage, and produces a control signal when the DC voltage is greater than the first predetermined voltage or less than the second predetermined voltage. The prompt module produces a prompt signal when receiving the control signal.