A method for managing a plurality of data blocks of a data storage device includes steps of: reading a plurality of data pages in the data blocks which having valid data; updating a plurality of access counts of the data pages in the data blocks; determining whether an access count of the data block is greater than or equal to an access count threshold, wherein the access count of the data block is selected from one of the access counts of the data pages therein; and when the determination is positive, storing data in the data block into a spare data block of the data blocks. The access count threshold is updated when an erase count of the data block is determined to be greater than or equal to an erase count threshold. A method of data management for a data storage device is also provided.