A pixel driving circuit with threshold voltage and power supply voltage compensation. The pixel circuit includes a storage capacitor, a transistor, a transfer circuit, a driving element, and a switching circuit. The transistor has a gate coupled to a discharge signal and is coupled between a first node and a second node. The discharge signal directs the transistor to turn on and then discharges the storage capacitor in a first period. The transfer circuit transfers a data signal or a reference signal to a first node of the storage capacitor. The driving element has a first terminal coupled to a first voltage, a second terminal coupled to a second node of the storage capacitor and a third terminal outputting a driving current. The switching circuit is coupled between the driving element and a display element. The switching circuit can be controlled to diode-connect the driving element in a second period, allowing the driving current to be output to the display element in a third time period.