The present disclosure relates to a data unit reuse method, where data is stored in a data unit in the form of a data block and the data block has a block ID. The method includes: successively reading each data block in a current data unit to search for a first specific data block whose block ID does not conform to a predetermined order; determining whether at least one data block whose block ID conforms to the predetermined order exists after the specific data block in the current data unit; when it exists, determining that the current data unit has been damaged, and when it does not exist, determining that a data block immediately previous to the specific data block is a data end.