A system for controlling backlight unit capable of reducing a time difference between an image displayed on a display panel and local dimming of the backlight unit, includes a plurality of dimming control devices configured to receive an input data packet including dimming data, and control local dimming of a light source, which is included in a region assigned in advance in a backlight unit, using the dimming data, a plurality of gate lines configured to electrically connect a predetermined number of dimming control devices and configured to be sequentially driven according to a row driving method, and a micro controller unit configured to generate a gate control signal for driving the plurality of gate lines and the input data packet.