A back light unit (BLU) having a plurality of luminous elements, and a control method thereof is provided. The BLU includes a temperature detector to detect a temperature of the BLU, brightness detectors to detect a brightness of the plurality of luminous elements, a voltage supplier to supply a driving voltage to the plurality of luminous elements, respectively, and a controller to perform a first adjustment to adjust the driving voltage supplied to the plurality of luminous elements according to the temperature detected at the temperature detector, and to perform a second adjustment to adjust the driving voltage supplied to the plurality of luminous elements according to the brightness detected at the brightness detectors. Accordingly, the temperature of the BLU can be maintained stable, and the brightness can be controlled uniformly.