Pixel driving circuit and display panel

The invention provides a pixel driving circuit and a display panel, and the pixel driving circuit inputs a first voltage to a first end of an energy storage capacitor through a threshold compensation loop in a threshold compensation stage, and charges the energy storage capacitor, so that the voltage of a second end of the energy storage capacitor reaches a second voltage. The data voltage is connected to the second end of the energy storage capacitor through the data write-in loop in the light emitting stage, so that the energy storage capacitor adjusts the voltage of the control end of the driving transistor to a third voltage based on the bootstrap effect; the driving transistor drives the light-emitting element to emit light based on the driving voltage received by the first connecting end and the third voltage received by the control end of the driving transistor through the light-emitting loop, so that the threshold voltage of the driving transistor can be compensated, and the light-emitting brightness