An apparatus for descrambling a data retrieved from an optical storage medium comprises a decoder, a memory and a descramble engine. The decoder decodes the data and generates address information corresponding to an address on the optical storage medium, wherein the address responding to a part of the data having been decoded. The memory stores the address information and the part of the data. The descramble engine continuously descrambles the part of the data by retrieving the address information. A method for descrambling a data retrieved from an optical storage medium comprises the following steps: decoding the data; generating address information corresponding to an address on the optical storage medium; storing the address information and a part of the data having been corrected; and descrambling the part of the data continuously by retrieving the address information after the data decoding is interrupted.