A voltage-programmed a-IGZO TFT pixel circuit for AMOLED display systems is proposed in this paper. Compensation schemes together with a simple driving strategy are proposed for threshold voltage shift and mobility variations of the driving TFT, as well as the OLED degradation. Simulation results indicate that the current error rates (CERs) are reduced to lower than 11.9% when the mobility variation of the driving TFT is ±30%, and 8.1% when the threshold voltage shift of the driving TFT is ±0.5 V, for the entire data input range.