Provided is an operation method for a memory device. The memory device includes a memory array having a plurality of word lines and a plurality of bit lines. The operation method for the memory device includes: applying a program voltage to at least one selected word line of the word lines; and during a high level of the program voltage, based on respective locations of a plurality of selected bit line, which are to be written into data 0, on the word lines, applying different plurality of bit line voltages to the selected bit line which are to be written into data 0.