Discussed is an OLED display device. The OLED display device includes a first transistor, a driving transistor, a first capacitor, a second transistor, an OLED, and a third transistor. The first transistor supplies a data voltage or a reference voltage to a first node according to a scan signal. A gate of the driving transistor is connected to the first node, a source of the driving transistor is connected to a second node, and a drain of the driving transistor is connected to a fourth node. The first capacitor is connected between the first and second nodes. The second transistor supplies a high-level source voltage to the second node. The OLED emits light with a difference voltage between voltages of the first and second nodes. The third transistor connects the fourth node to a fifth node according to a second emission control signal.