A mobile communication device including a system ground plane, an antenna, a signal distributor, a transceiver and a sensing controller is provided. The antenna converts an electromagnetic wave to a radio-frequency signal. Besides, the antenna and the system ground plane form a sensing capacitor to detect an object and generate a detecting signal accordingly. The signal distributor is electrically connected to the antenna through a first connection terminal and a second connection terminal and guides the radio-frequency signal and the detecting signal from the antenna to a third connection terminal and a fourth connection terminal. The transceiver is electrically connected to the third connection terminal and processes the radio-frequency signal. The sensing controller is electrically connected to the fourth connection terminal and determines whether the object exists around the antenna according to the sensing signal.