A pixel driving circuit of an organic light emitting diode display panel includes a scan TFT, a Vdd-connected TFT, a driving TFT, a diode-connected TFT, a storage capacitor, a reset TFT, an OLED-connected TFT, and an organic light emitting diode. A reset TFT is connected to the diode-connected TFT and a previous scan line. An OLED-connected TFT is connected to the driving TFT and the light-emitting line. An organic light emitting diode is connected to the OLED-connected TFT and the ground. The amount of output current to the OLED does not depend on the threshold voltage of the driving TFT and only depends on the amount of the data signal voltage to be written. Thus, the variance in the threshold voltage of the driving TFT caused by the factor of the manufacturing process can be compensated to improve the non-uniform image defect.