An audio device and an audio input/output method are described, which is coupled to an audio port, and includes a capacitor, a load, an output amplifying module, and an input amplifying module. The capacitor and the load are coupled to the audio port. The output amplifying module is operated at a first working voltage, for outputting a first audio signal to the audio port. A direct current (DC) level of the first audio signal is substantially zero volts. The input amplifying module is operated at a second working voltage, in order to receive a second audio signal from the audio port. When the audio port is in an output state, the output amplifying module is enabled and the input amplifying module is disabled, and when the audio port is in an input state, the input amplifying module is enabled and the output amplifying module is disabled.