An organic light-emitting diode display device comprising: an organic light-emitting diode display panel on which subpixels are disposed; a gamma reference voltage supply circuit adapted to supply gamma reference voltages (GMAmax-GMAmin) and to vary the gamma reference voltages supplied during a sensing operation for sensing a threshold voltage in respect to the gamma reference voltages supplied during a driving operation; a data driver adapted to supply data voltages (Vdata) based on the gamma reference voltages to data lines, wherein the data driver is adapted to sense a voltage (Vsen) of a sensing node within each of the subpixels in the sensing operation; and a timing controller adapted to control the data driver, wherein the timing controller is adapted to perform a compensation process based on the voltage (VSen) sensed by the data driver, wherein the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a first voltage range during the driving operation and the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a second voltage range during the sensing operation for sensing the threshold voltage (Vth) of the sensing node, wherein the first voltage range is greater than the second voltage range; characterized in that: the sensing operation for sensing the threshold voltage includes an initial threshold voltage sensing operation and an updating operation of sensing a change of the initial threshold voltage, and the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a greater voltage range during the initial threshold voltage sensing operation than during the updating operation of the threshold voltage. an organic light-emitting diode display panel on which subpixels are disposed; a gamma reference voltage supply circuit adapted to supply gamma reference voltages (GMAmax-GMAmin) and to vary the gamma reference voltages supplied during a sensing operation for sensing a threshold voltage in respect to the gamma reference voltages supplied during a driving operation; a data driver adapted to supply data voltages (Vdata) based on the gamma reference voltages to data lines, wherein the data driver is adapted to sense a voltage (Vsen) of a sensing node within each of the subpixels in the sensing operation; and a timing controller adapted to control the data driver, wherein the timing controller is adapted to perform a compensation process based on the voltage (VSen) sensed by the data driver, wherein the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a first voltage range during the driving operation and the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a second voltage range during the sensing operation for sensing the threshold voltage (Vth) of the sensing node, wherein the first voltage range is greater than the second voltage range; characterized in that: the sensing operation for sensing the threshold voltage includes an initial threshold voltage sensing operation and an updating operation of sensing a change of the initial threshold voltage, and the gamma reference voltage supply circuit is adapted to supply gamma reference voltages (GMAmax-GMAmin) having a greater voltage range during the initial threshold voltage sensing operation than during the updating operation of the threshold voltage.