An audio output circuit applied in an electronic device includes a filter capacitor and a transistor. A base of the transistor is connected to an audio processing unit, an emitter of the transistor is connected to a voltage port, a processor and an earphone detecting unit of the electronic device is electrically connected to a collector of the transistor. The filter capacitor is connected between the base of the transistor and the ground. The filter capacitor filters the audio signals generated by the audio processing unit, to ensure that and the transistor is always turned on.