The present disclosure provides a memory management method for a rewritable non-volatile memory module. The rewritable non-volatile memory module includes physical programming units, each of which includes multiple bits. The memory management method includes: identifying a first physical programming unit by applying a predetermined read voltage, where the first physical programming unit is identified as in a fully-erased status; identifying a second and a third physical programming units which are programmed before the first physical programming unit; acquiring status data of the second and the third physical programming unit; computing a difference of the status data between the second and the third physical programming unit; if the difference is larger than a threshold, identifying the second physical programming unit as in a program failure status.