Provided are a pixel driving circuit, a driving method thereof and a display panel. The pixel driving circuit includes a pixel driving module, an ultrasonic driving unit, an ultrasonic sensing unit and a signal acquisition unit. The pixel driving module is configured to drive a light-emitting unit to emit light; the ultrasonic driving unit is configured to provide a signal of a second signal terminal to a first node under control of the second signal terminal; the ultrasonic sensing unit is configured to transmit ultrasonic waves according to signals of the first node and a third power supply terminal, receive reflected ultrasonic echoes and generate a first induction signal at the first node; the signal acquisition unit is configured to output a second induction signal to an output terminal according to a first power supply terminal and first induction signal of the first node under control of the first node.