The invention provides a data storage device. In one embodiment, the data storage device is coupled to a host, and comprises a flash memory and a controller. The flash memory comprises a spare block pool and a data block pool, wherein the spare block pool comprises a plurality of spare blocks, and the data block pool comprises a plurality of data blocks. The controller receives target data from the host, writes the target data to a current programming data block, determines whether a current programming page is a first page of the current programming data block, determines whether data move information is set when the current page is not the first page, and when the data move information is set, perform a data move process according to the data move information within a limited time period.