Block management and change method, flash memory storage system and controller thereof

The invention relates to a block management and change method for a flash memory, a flash memory storage system and a controller thereof. The block management and change method comprises the following steps of: dividing multiple physical blocks of the flash memory into multiple physical units, and grouping into a using area and a substituting area, wherein the physical blocks of each physical unit can be accessed by using a multi-block surface access order; when the physical blocks of the physical units of the using area are damaged, if the alternate area stores good physical units, changing the damaged physical units by taking the physical units as units, and recording undamaged physical blocks of the substituted physical units; if the alternate area does not store the good physical units but good physical blocks, changing the damaged physical blocks by taking the physical blocks as units, thus the access efficiency of the flash memory is enhanced, and the service life of the flash memory is prolonged.