A memory management method for a rewritable non-volatile memory module including a plurality of physical unit groups is provided, and each physical unit group includes first physical units. The method includes: grouping the physical unit groups into a first and second areas, setting the physical unit groups of the first area in a first program mode indicating that all physical units are programmable, and setting the physical unit groups of the second area in a second program mode indicating that only the first physical units are programmable. The method also includes: when a physical unit group in the first area is damaged, transforming a physical unit group from the first program mode to the second program mode and the physical unit group is unable to be set back in the first program mode. Accordingly, the lifespan of the rewritable non-volatile memory module is increased.