Disclosed is an access method of a non-volatile memory device which comprises detecting a threshold voltage variation of a first memory cell, the a threshold voltage variation of the first memory cell being capable of physically affecting a second memory cell; and assigning the second memory cell to a selected sub-distribution from among a plurality of sub-distributions according to a distance of the threshold voltage variation of the first memory cell, the plurality of sub-distributions corresponding to a target distribution of the second memory cell.