A mobile communication device capable of communicating with a remote communication device includes a communication unit, a microphone, an input unit, a control unit, and a switching unit. The communication unit is used for generating a remote audio signal according to remote audio information received from the remote communication device. The microphone is used for generating a local audio signal according to a local sound. The input unit is used for receiving a trigger signal. The control unit is configured for generating a switching signal in response to the trigger signal. The switching unit is configured for transmitting the remote and local audio signals to the remote communication device via the communication unit alternately according to the switching signal.