An I/O interface cover assembly includes a panel, a bracket for accommodating an I/O interface element, a driving device, a locking device and a button. The panel defines an opening and a button hole adjacent the opening. The bracket is received in the opening, and includes one end pivotally connected to the panel and the other end defining an I/O slot and a locking hole therein. The driving device is disposed between the panel and the bracket for driving the bracket out from the opening of the panel. The locking device is movably arranged to the panel, and engagable with the locking hole of the bracket. The locking device is disposed with a resilient element. The button is disposed in the button hole of the panel, and is able to press the locking device to disengage from the locking hole of the bracket.