A pixel driving circuit and a display panel are provided by the present application. An electrical potential of a control terminal of a driving module can be kept stable through a detection module by connecting the detection module with a control terminal of the driving module when detecting a threshold voltage of the driving module. In this way, an obtained threshold voltage of the driving module is accurate, to make the threshold voltage of the driving module can be accurately compensated, and a display uniformity and a stability of the display panel are improved.