A cover plate for an optical disk drive designed to reduce disk vibrations and noise is provided. The cover plate is installed above a main frame of the optical disk drive and has a through hole in the center through which a disk clamp for clamping a disk placed on a turntable is fitted and a projection formed to oppose the disk up to a predetermined height in order to narrow a gap with the disk. Furthermore, the cover plate has a circular step formed opposite a surface corresponding to an outer circumference of the disk in the shape of an annular groove for lowering acoustic energy density of noise. The cover plate constructed in this way reduces disk vibration due to air damping effects resulting from a narrow gap between the disk and the cover plate while suppressing noise due to the presence of the abruptly expanded portion. Furthermore, the cover plate can be implemented without a separate device by making simple changes to the structure of cover plate.