Memory device and programming method thereof

The invention provides a memory device and a programming method thereof. The memory cell array comprises a first virtual word line group, a plurality of word lines and a second virtual word line group which are arranged in sequence. The programming method includes: dividing a plurality of word lines into a plurality of word line groups; generating at least one group of non-selective bias voltages, the at least one group of non-selective bias voltages comprising a plurality of non-selective bias voltages respectively corresponding to each of the plurality of word line groups; selecting one of the plurality of word lines for programming, and judging that the selected word line belongs to a specific word line group of the plurality of word line groups; and applying a corresponding non-selection bias voltage in a plurality of non-selection bias voltages corresponding to the specific word line group in the at least one group of non-selection bias voltages to one of the virtual word lines in one of the first virtua