Abstract: This invention relates to a flat panel display device that is adaptive for optimizing data, which are to be displayed in a panel defect area, in used of a compensation value of a compensation circuit as well as compensating defect pixels by a repair process, and a method of controlling a picture quality thereof. A flat panel display device according to an embodiment of the present invention includes a display panel; a memory which stores a first compensation data, a second compensation data and a third compensation data; a first compensation part; a second compensation part; a third compensation part; and a driver for driving the display panel in use of the data modulated by the first to third compensation parts.