A memory device and an enhance programming method thereof are provided. The enhance programming method includes: performing program and verifying operations on a plurality of memory cell groups of a memory division, where each of the memory cell group corresponds to at least one byte; calculating a programming time for completing program operation of each of the memory cell groups; setting an indication flag when the programming time is larger than a preset threshold value; and, when the indication flag is in a setting state, increasing at least one of a plurality of program operation parameters, and performing an enhancement programming operation on the memory cell groups of the memory division.