A hard disk-mounting module includes a drawable mounting frame and at least one tray member. The mounting frame includes a frame body, and at least one electrical connector mounted on the frame body and adapted for electrical connection with a hard disk. The tray member is adapted to carry the hard disk thereon, and is slidably mounted on the frame body so as to be slidable relative to the electrical connector between a connecting position, in which the hard disk carried by the tray member is electrically connected to the electrical connector, and a disconnecting position, in which the hard disk is electrically disconnected from the electrical connector.