The present disclosure relates to a backlight source based on grapheme including a lower substrate, an upper substrate and a first insulation layer, multiple gate electrodes, a second insulation layer, multiple graphene quantum dot layers, and multiple groups of source electrodes and drain electrodes sequentially disposed there between. The multiple graphene quantum dot layers are separately disposed on the second insulation layer, and one source electrode and one drain electrode are disposed on each graphene quantum dot layer. A field color sequential LCD and a driving method are also disclosed. Through controlling the gate voltage of the backlight source based on graphene, the backlight source has a precise region light control ability to avoid a color gamut reduction phenomenon because of the color crosstalk.