A driving method of display device for a display device capable of reducing flicker due to refresh rate variation includes: determining whether a processor of the display device is generating a vertical blank interval of an image signal, wherein said vertical blank interval is next to a last frame data period thereof, and the last frame data period is for a last frame to be displayed by a display panel; and activating a data line of the display panel with a balancing voltage related to data of a line of the last frame when the processor is generating the vertical blank interval, wherein a plurality of sub-pixels of the display panel connects to the data line, the data of the line of the last frame are sequentially transmitted to the plurality of sub-pixels in the last frame data period for displaying the last frame. Said display device is also disclosed.