A data storage system includes a first memory, a controller, a counting module, and a checking and correcting module. Copyback operations are performed in the first memory. The controller couples the first memory to the counting module and the checking and correcting module. The counting module provides a counting operation for the copyback operations at different logic addresses of the first memory and, according to a counting result of the counting operation, determines whether a checking and correcting requirement has been satisfied by any of the logic addresses. The checking and correcting module receives data read out from the first memory, wherein the received data corresponds to a satisfying logic address, and checks the received data and corrects the received data when it is checked that the received data is incorrect, to correct the first memory accordingly.