Method for eliminating track shift component in focusing error signal of optical storage system and device thereof

A method and a device for eliminating track shift component in focusing error signal of optical storage system are applied to an optical storage system. The optical storage system consists of an optical pickup head that is used to generate a RF ripple signal, a track locking error signal and a focusing error signal, and a focusing device that lets light spot be focused on a disc according to the focusing error signal. The method and the device utilize a track shift component that is composed of the RF ripple signal and the track locking error signal in the focusing error signal, and then feed the component to the focusing device to eliminate the track shift component in the focusing error signal. The focusing control signals can be further effectively reduced while crossing tracks, thereby elevating the product performance and stability.