A pixel driving circuit for use in an active matrix organic light-emitting diode with threshold voltage compensation includes a transistor, a first capacitor and a second capacitor. The organic light-emitting diode is in communication with the transistor. The first capacitor has a first and a second ends, wherein the first end is coupled to a gate electrode of the transistor. The second capacitor has a third and a fourth ends coupled to the second end of the first capacitor and a ground voltage, respectively. A threshold voltage of the transistor is stored in the first capacitor in a first state, a driving voltage received from a data line is stored in the second capacitor in a second state, and the gate electrode of the transistor is biased with a specified voltage applied to the first and the second capacitors interconnected in series in a third state. A current passing through the organic light-emitting diode is controlled accordingly.