Method and apparatus for driving a plasma display device to improve a gradation display during the plasma display device is driven at a relatively high frame frequency. The driving method includes separating a unit frame of an input image signal into first and second subfield groups; and deciding a gradation of each of the subfield groups to display the gradation in a first frame frequency when a minimum gradation level of the first or second subfield group is equal to or below a first reference level, and to display the gradation in a second frame frequency when the minimum gradation level exceeds the first reference level.