A display device includes a display panel, a light source module and a control unit. The display panel includes plural display areas. The light source module includes plural light source units. The light source units are configured to output plural light beams to illuminate the display areas of the display panel. The control unit is coupled to the light source module and configured to receive a frame data. The frame data includes plural subframe data, and the subframe data are displayed on the display areas. The control unit is further configured to control a first light source unit of the light source units to adjust a brightness corresponding to a first color of a first light beam of the light beams according to a ratio of the first color. The ratio of the first color is related to a first subframe data of the subframe data.