A system for supplying a driving voltage to move an optical pickup unit to a predetermined position includes a storage unit, an output unit, and a drive module. The storage unit is used for storing instructions. The instructions include a move-outwards instruction, a move-inwards instruction, and a move discriminate-position instruction. The output unit is constructed and arranged for outputting the instructions. The drive module is coupled to the output unit for supplying the driving voltage to move the optical pickup unit toward an outermost position based on the move-outwards instruction, move the optical pickup unit to an innermost position based on the move-inwards instruction, and move the optical pickup unit from the innermost position to the predetermined position based on the move discriminate-position instruction.