Abstract: A disk ejection device of a portable computer and controlled method thereof, the disk ejection device includes a cover installed on a computer body of the portable computer, at least one torsional spring coupled between the computer body and the cover for providing a preliminary torque force to let the cover be in a closed state, and a controlled button disposed on the computer body for controlling a disk ejection thereby to push the cover. Furthermore, the prior optical disk drive can be replaced by the other optical disk drives with different size-designed front boards, and the portable computer still can have a good-looking appearance due to the cover.