A portable electronic device capable of signal or power transmission and standing on a surface in a vertical or near-vertical orientation at the same time is provided in the present invention. The portable electronic device includes a flat body having a front surface, a rear surface opposite to the front surface, and a through hole passing through the flat body, and the through hole extending from the front surface to the rear surface. Herein the through hole is adapted to couple with an external docking element for signal or power transmission. Thus, the portable electronic device is capable of signal or power transmission and standing on the supporting surface at the same time via the external docking element coupling with the through hole.