An organic light emitting display (OLED) includes a voltage adjustment unit for adjusting a preliminary control voltage according to a second reference voltage, a couple unit for coupling a change of the preliminary control voltage to adjust a control voltage, a driving unit for providing a driving current and a driving voltage according to the control voltage, a first reset unit for resetting the driving voltage according to a first reference voltage, a second reset unit for resetting the control voltage according to the driving voltage, an organic light emitting diode for generating output light according to the driving current, and an emission enable unit for providing a control of furnishing the driving current to the organic light emitting diode. Through the circuit operation of the reset units and the voltage adjustment unit, occurrences of image retention phenomenon and pixel brightness distortion on the OLED screen can be avoided.