Pixel driving circuit and display panel

The utility model provides a pixel driving circuit and a display panel, and belongs to the technical field of display. The pixel driving circuit comprises a driving transistor used for generating driving current, a channel region of the driving transistor is made of metal oxide semiconductor materials, and the driving transistor is only provided with one of a top gate and a bottom gate. According to the pixel driving circuit and the display panel, an upper and lower double-gate structure of a driving transistor in the pixel driving circuit can be changed into one of a top gate and a bottom gate, and the electron mobility of the driving transistor is reduced, so that the sub-threshold swing of the driving transistor is increased, and the low-gray-scale image quality of the display panel can be improved.