An LCD and a backlight module driving device and a method thereof are provided. The method is adapted to drive at least one backlight unit in a backlight module. The backlight unit is used for supplying a surface light source to an Nth area pixel of the LCD panel, where N is a positive integer. The method includes the following steps of first calculating a time of the Nth area pixel under a stable state in a frame period and then providing a control signal to drive the backlight unit when the Nth area pixel is under the stable state in the frame period.