Memory device and erasing method thereof

A memory device, comprising:

• a memory;
• and
• an erasing module, configured to determine whether a memory passes a first erasing verification operation according to a first erasing verification threshold, when the memory does not pass the first erasing verification operation, the erasing module generates at least one erasing pulse, corresponding to an erasing size, according to an erasing number so as to perform an erasing operation on the memory, when the memory passes the first erasing verification operation, the erasing module generates a flag, wherein the flag indicates that all addresses of the memory have passed a first erasing verification, and determines whether the memory passes a second erasing verification operation according to a second erasing verification threshold, when the memory does not pass the second erasing verification operation, the erasing module generates the at least one erasing pulse, corresponding to the erasing size, according to the erasing number so as to perform the erasing operation on the memory, when the memory passes the second erasing verification operation, the erasing module performs an over-erase correction on the memory, the erasing module determines whether there is the flag indicating that all addresses of the memory have passed the first erasing verification, when there is no flag indicating that all addresses of the memory have passed the first erasing verification, the erasing module determines whether the memory passes the first erasing verification operation according to the first erasing verification threshold, and when there is the flag indicating that all addresses of the memory have passed the first erasing verification, the erasing module determines whether the memory passes the second erasing verification operation according to the second erasing verification threshold.